Twayne and Callie must infiltrate a secret Wizard compound where Leonard is training his apprentice. But their complicated strategy involves building a summer camp on a moment's notice, with Mark Lilly as their head counselor.
Callie's parents get back together and have a new baby. But when their marriage falls apart again, Callie must play guardian to this younger, hotter spawn of the devil.
Grimes loses it when his favorite TV series ends with a stupid twist. Mark helps him unravel his attachment to the show, uncovering a deep seated memory along the way, while amateur filmmaker Randall documents the whole thing.
Mark finds a magic ring in Leonard's desk drawer. When he puts it on, he mistakenly activates an engagement that Leonard put on ice centuries before, when dragons (Todd Barry) roamed the earth.
Callie decides to makes a clone of Mark so that the DOI Bowling Team will win their tournament. But when Clone Mark finds a cruel message in Callie's secret diary, he decides to get revenge by framing her for murder.
Randall puts Mark's soul up for sale on the Soul Exchange, and finds interested buyers in Callie and Aldermach. Meanwhile, Grimes pursues his dream of creating a pop music act with a new teen sensation.
Twayne throws a company party aboard a cruise ship, where Randall is introduced to a strange plant species. Randall gets sick from its dangerous pollen, and finds that Mark holds the key to his survival.
With Mark working all the time, Randall feels neglected, so he decides that they should spend more time together to decide if they should stay roommates. And Grimes's Mummy returns from the dead, only to find fault with everything Grimes is doing.
Callie reveals to Mark that she's been sleeping with other guys. So when Mark's college girlfriend (Jenny Slate) shows up, he decides to put his newly "open relationship" with Callie to the test.
Mark becomes conflicted about his relationship with Callie after she gets a promotion by turning herself into a man. He does his best to be understanding, but their love is soon put to the test when they are asked to embark on a dangerous mission to the fabled underwater city of Atlantis.
