In "Everything Breaks" Billy is out of control, so Mandy enlists Lord Pain to help her set Billy straight. In "The Show That Dare Not Speak Its Name" Billy accidentally summons Pinface, a supernatural being bent on world domination.

In "The Secret Snake Club vs. P.E." all the boys try to get out of physical education using all kinds of schemes. In "King Tooten Pooten" Irwin discovers that he's a pharaoh's heir, and decides to build himself a pyramid.

In "Billy Gets an A" Grim magically changes Billy's grade from F to A, which disturbs the fabric of reality. In "Yeti or Not, Here I Come", Grim tries to rip the Abominable Snowman who has been cheating death for a very long time.

In "Nergal's Pizza", Nergal and Grim start rival pizza franchises. In "Hey, Water You Doing?", a trip to a water park goes south when Billy, Mandy and Grim all wind up underwater and a mermaid falls in love with Billy.

In "Company Halt", Hector Con Carne and his army arrive in Endsville and try to lure Skarr back to their side. In "Anger Mismanagement", Grim, Skarr and Mandy all receive help in trying to keep their tempers in check.

In "Waking Nightmare" Billy tries to keep Mandy awake to make her fail a school test the next day. In "Beware of the Undertoad" Billy is terrorized by a toad-like sea creature.

In "The Most Greatest Love Story Ever Told Ever" Nergal Jr. accidentally asks Mandy to the Valentine Day dance, making Irwin jealous. In "Detention X" Grim becomes a substitute teacher and sends all the kids into the Detention Dimension.

Alien werewolves from the Moon attack Earth and steal all the cheese. It's up to Mandy, Grim, Billy, and Sperg to stop the alien ploy.

The Spider Queen wants to take revenge on Grim for denying her the rightful place as the Ripper.

In "Dracula Must Die!" Lionel Van Helsing wants to kill Dracula for stealing his girlfriend, and Grim tries to save his childhood hero. In "Short Tall Tales" Grim tells ridiculous stories about Pecos Billy, Paula Bunyan, and John Henry.

In "Nigel Planter and the Order of the Peanuts" Nigel steals Grim's scythe to exact revenge on his former school. In "The Incredible Shrinking Mandy" Billy uses the scythe to shrink Mandy, but messes up and she starts to grow instead.

In "El día de los muertos estupidos" the gang travels to Mexico where Billy finds his long lost twin brother. In "Heartburn" Billy and Mandy use Grim's camera that reveals true heart, and discover a disturbing truth about Irwin.