With help from Danny Phantom, Tucker Foley, Jazz Fenton, and new characters Rachel Dawson, Diane Kiyoko, and Greg Osbourne, Sam is chosen to fight monsters, vampires, demons, zombies, werewolves, and other forces of darkness who try to attack her friends, her school, Amity Park, and the entire planet.
Starting off two weeks after Danny Phantom's series finale, "Phantom Planet", Sam Manson becomes a chosen one to hunt down monsters and other forces of darkness who try to attack her friends, her school, Amity Park, and the whole world, equipped with rifle guns, tranquilizer guns, TNT, a blade (for slashing down zombies), silver objects (for stopping werewolves and werecats), stinkbombs (for scaring off monsters and vampires), a sunstone amulet (for killing vampires), a blaster loaded with garlic water (for making vampires itch), stakes (for stabbing vampires to death), large nets, a blaster loaded with hot sauce (for hunting down zombies), seven gas masks (for protection against stench and smoke; one given to her, the other six given to Danny, Tucker, Jazz, Greg, Diane, and Rachel), a pair of welding goggles (for eye protection against sand, fire, and light), a walkie talkie, and flashlights. Later, zombies emerge from the grave and try to attack Amity Park and Sam and the gang have to stop them all.
After hunting down vampires by curfew and going to bed, a friendly vampire (who turns out to be her cousin Sheila) comes to Sam's house to help Sam save her from the sun, which she will crumble to dust soon, so she can hide her in the basement closet before her parents see the vampire in her house. When night falls and with Sam's parents out, Sheila wants to hang around with Sam and talk to her that hundreds of years ago she was a vampire slayer, until a vampire bit her and she got turned into a vampire, and the vampire spell became permanent. Sam offers Sheila to eat some fruits and vegetables and to drink juice, until Valerie Gray (her enemy) kidnaps the vampire and attempts to slay her. Then Sam must stop her from killing her cousin. (Note: This is only one of two episodes of the series (the second being "The Giant Gila Monster") to not feature Danny, Tucker, Jazz, Rachel, Diane, and Greg, their brief appearances, or mentions of them. Also, for the first time in Danny Phantom history, Sam is tied to a chair and gagged by Valerie who tries to stab Sheila with a stake of her own. Aside from her non-speaking cameo in "Monster Hunter in Training", this is Valerie's first official appearance in the series spinoff. This is not the first time Valerie is the villain of an episode. Last series she tried to hunt down Danny Phantom with her ghost-hunting weapons and destabilize Dani Phantom in order to research her for a better clone. Sam's cousin Sheila would make four more appearances of this series spinoff. Check out her reaction when she first sees Sheila.)
When Danny, his mom Maddie, Sam, and the gang visit Arkansas to visit his aunt Alicia, a scarecrow comes to life and scares away residents of the state. (Note: This is one of only three episodes of the series (the others being "Escape From The Computer" and "The Siren's Shriek") where Maddie appears without her husband Jack, although she does mention his name there.)
Sam, Jazz, Rachel, and Diane are spray-painting logos on T-shirts to sell them at the mall, but when someone releases a contagious virus that turns everyone, including, Danny, Tucker, and Greg, into mindless monsters, it's up to the girls, equipped with gas masks, to save the day. (Note: This is very similar to Motorcity's "Going Dutch".)
A giant bat-like flying monster causes the whole population of the world (including Danny, Tucker, Jazz, Rachel, Diane, and Greg) to be frozen, except for Sam, who remains immune from being frozen and has to attack it in order to make her friends free. (Note: This is very similar to Sym-Bionic Titan's "I Am Octus", and Sam is Octus to Danny's Lance.)
Sam tries to get Danny and the gang to believe that her vampire cousin named Sheila comes to visit Amity Park, but they never believe her since vampires never exist. However, when Sheila comes in, she disguises herself in human form, acting like Amity Park's transfer student. Later, despite no one believing Sam, Sheila's evil vampire brother invades Amity Park and turns Sam into a vampire, and it's up to Danny and the gang to stop him and then revert her to normal. (Note: In last series' episode "Beauty Marked", Sam wore fake vampire fangs when she auditioned for the beauty pageant. For this episode she wears them again, believing Danny and his friends what a vampire does and looks like and bites Rachel in the neck. We should find out later in the episode when she gets bitten by Sheila's vampire brother and turned into one. This is most likely one of just a few episodes where Sam isn't the protagonist but a villain. Plus, like she was in a couple of early episodes of last series, Valerie Gray is voiced by Grey Delisle in a cameo appearance during her job as a Nasty Burger waitress, just like she did in "Double Cross My Heart". When Sam gets bitten by Sheila's brother and turned into a vampire, her voice is similar to Vegetized Sam's.)
Everyone is attending a Halloween dance at Casper High and Sam's vampire cousin Sheila is joining them when Sheila's evil father shows up, turning Amity Park (and later the whole planet) into vampires, and is up to Sam, Danny, Tucker, Jazz, Rachel, Diane, Greg, and Sheila to stop him. That is, until Sam, Danny, Tucker, Jazz, Rachel, Diane, and Greg are turned into vampires too, one by one, until only Sheila can save all her friends--by destroying her father with sunlight. (Note: Among the people who get bitten and get turned into vampires include Danny, Tucker, Jazz, Dash, Kwan, Paulina, Star, Jack and Maddie Fenton, Jeremy and Pam Manson, Angela and Maurice Foley, Mr. Lancer, Ms. Tetslaff, Principal Ishiyama, and later Rachel, Diane, Greg, and Sam Manson. This is very similar to Archie's Weird Mysteries' "Halloween of Horrors". Also, it is the first of only six episodes without a cold opening and title card, the others being "Island Of The Lost", "Return Of The Living Dead", "Thanksgiving Witch Switch", "Sam Saves Christmas", and "The Ultimate Enemy". Plus, it is the first of six hour-long movie episodes of the series.)
After being swept away in a whirlpool from a boat trip across the sea, the gang get stranded on a very strange island populated by dinosaurs and other prehistoric animals. However, things go wrong when large meat-eating dinosaurs try to eat them, pterodactyls and plesiosaurs try to attack them, and saber-toothed cats try to kill them, until Sam has to stop them using her tranquilizer gun, in order for the gang to survive and try to escape the island. (Note: This episode shares references to 1993's "Jurassic Park"; the dinosaur landscape scene, a Dilophosaurus that squirts venom out of its mouth and opens its neck frill, and a scene where two of whom sleep in a tree when a sauropod browses on leaves. For a list of animals seen in this episode, click here.)
A werecat bites Paulina and Star, turning them into werecats. Sam and Valerie find a way to break the werecat's curse, while Danny and Tucker, infected with ecto-acne, are taken by Maddie and Jack to the hospital for a cure. (Note: Werecat Star is orange with red stripes and green eyes, while werecat Paulina resembles T.U.F.F. Puppy's Kitty Katswell. Sam poses herself as a cheerleader (like she did in "Reality Trip") to infiltrate them in the football scene. In the flashback scene at the beginning of this episode, Sam survived from getting infected with ecto-acne, while wearing her gas mask, but neither Danny nor Tucker did, even they forgot to bring their gas masks with them! We learn in this episode that Sam is allergic to cats.)
A huge mutant leech sends his swarm of mind-controlled leeches to turn everyone, including Tucker, Jazz, Rachel, Diane, Greg, and Danny's parents, into mindless zombies to destroy Danny and Sam and take over the world. With Danny and Sam the only survivors left in Amity Park, they have to do one thing: invent an ice gun to stop them. (Note: In last series' episode, "Urban Jungle", Undergrowth possesses everyone using his mind vines. Like it did before, the mutant leech's swarm of mind-controlled leeches do the same thing to everyone else besides Danny and Sam. The mind leeches resemble mind vines but they are blue-violet and grow up to seven feet in length. The only way to kill a mind leech is to freeze one and destroy it, turning its host back to normal. When a host gets mind-controlled by a leech, his/her eyes become blue instead of green. The solution to destroy the mutant leech is to kill him with liquid nitrogen, which causes all the mind leeches to die, making everyone back to normal.)
Amity Park is infested with zombies, and it is up to Danny, Sam, Tucker, Jazz, Rachel, Diane, and Greg for an attempt to kill them using hot sauce. But it fails when more and more zombies show up and bite the group, leaving Sam the only survivor left, until Sam finally wakes up and finds that she was having a very bad dream. (Note: This is very similar to the 6teen Halloween special, "Dude Of The Living Dead". Not to be confused with the 1985 movie of the same name.
The gang head for Salem, Massachusetts, to meet Sam's friendly witch cousin named Sara (who also looks like her except with very long black hair with red highlights, dark green eyes, dark red lipstick, dark red fingernails, paler skin, a black and red dress with red sleeves draping down her shoulders, black ankle shoes with red tints, red and black fingerless gloves that end at the elbow, and a red bat necklace) for Thanksgiving. However, things go out of control when Sam gets mistaken for a witch and is going to be burned at the stake, until Sara uses her magic to save her from being killed. Unfortunately for Sam, Sara's mother (a wicked witch) tries to get revenge on her, until it's up to her friends to stop her and save Sam from being petrified. (Note: The scene where Sam Manson is mistaken for a witch was also recycled from the same scene in Danny Phantom's "Infinite Realms". The only difference is that her hands are tied to the stake and she's gagged overnose. Plus, Sara will appear again later in this series. In fact, Sara is very similar to the Hex Girls' Thorn from "Scooby Doo & The Witch's Ghost", with the same wardrobe and voice actor.)
During the Mansons' road trip to an annual event in Nevada, a giant Gila monster terrorizes the state's residents and Sam tries to stop the lizard before they make it there. (Note: Not to be confused with the 1959 episode of the same name.)
Tucker does a spell to make a character he's crushing on from an old dinosaur action film come to life, only to have Deinonychuses in that same film come to life as well, until the gang must stop them and bring them all back where they came from. (Note: The Deinonychus scene is a reference to the Velociraptor scene of 1993's Jurassic Park. Not to be confused with the Archie's Weird Mysteries episode of the same name.)
The gang goes to the California harbor to go sightseeing...only to discover a very large octopus terrorizing the place and attacking people on the pier, turning them, including Sam's friends, into humanoid sea zombies. Sam has to find a way to stop the octopus in order to rescue them and her friends from its lair. (Note: This is a reference to the 1955 movie, "It Came From Beneath The Sea". When Sam is laying bound and gagged, she is tied hand and foot in seaweed and gagged overnose by a large starfish. Although seaweed is easy to come off, the only problem is that the starfish is very hard for her to pull it off.)
Every male and female are affected by a call of a very dangerous siren with a woman's body and a bird's wings and feet, and it's up to Sam, Jazz, Rachel, Diane, and Maddie to stop her. Except that Danny, Tucker, and Greg are at Chicago's Shedd Aquarium with their social group.
Rachel gets bitten by a chameleon, who turns out to be none other than a shapeshifter out to switch bodies with her, until the gang tries to find out which one the real Rachel is. (Note: This is a reference to Are You Afraid Of The Dark's "The Tale Of The Chameleon".)
A huge man-eating plant resembling Audrey II invades Amity Park from the forest, spitting out seeds which pucker up into smaller man-eating plants resembling Piranha Plants, and it's up to Danny and Sam to attack the plant using Danny's freezing powers and Sam's blade. (Note: Not to be confused with "Urban Jungle".)
A large dinosaur Spinosaurus escapes from time and goes and Sam has to stop the monster. The problem is that she activates the wrong time period and goes back to 1885, the 1500's, the pirate age, the year when Sam was born, and the future when Sam becomes 25 years old. (Note: Spinosaurus is very similar to the one from 2001's "Jurassic Park 3". Sam's future self resembles Terminatra of last series' episode "Memory Blank" except with purple eyes and lipstick, skin covering the right half of her face, her right arm, and the same ponytail Sam has but much longer.)
A huge 300-foot-tall killer monster (resembling the Cloverfield Monster) tries to destroy the whole planet and attack its population with his lion-sized prasites, until the gang, as well as Jack and Maddie Fenton, Dash Baxter, Paulina, Star, Kwan, Valerie Gray, Sam's supernatural cousins Sheila and Sara, Danny Phantom's ghost enemies (including the Box Ghost, Lunch Lady Ghost...) and Sam's monster enemies (including vampires, zombies, witches, dinosaurs...) must stop the beast in order to save the world. (Note: In this series finale, many of Danny Phantom's ghosts (including Lunch Lady Ghost, Box Ghost, Technus, Skulker, Ember, Spectra, Bertrand, etc.) all make a guest appearance, and many of Sam Manson's monster enemies from the show's previous episodes return.)