Callie and Twayne build a summer camp as part of their plot to infiltrate a secret wizard compound where Leonard is training his apprentice.

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.

The end of his favorite TV series, "Dishonorable Discharge" sends Grimes off the deep end. Mark has to help him get to the bottom of his inexplicable attachment to the show, uncovering a deep seated memory along the way.

Mark inadvertently learns of a plot to end humanity when he's drafted into Satan's Dark Army with Twayne.

After Mark finds a ring in Leonard's desk, he inadvertently activates the wizard's engagement from a bygone era, when dragons roamed Earth.

Callie hopes that making a clone of Mark will guarantee the Department of Integration's win in a bowling tournament, but the plan backfires when the duplicate tries to frame her for murder.

Randall's idea to sell Mark's soul on the Soul Exchange draws interest from Callie and her father. Meanwhile, Grimes thinks he's found the next great pop-music sensation.

Twayne throws a company party aboard a cruise ship; Randall gets sick from dangerous pollen.

Callie reveals to Mark that she's been sleeping with other guys, while a girlfriend from Marks past returns with a dark secret.

Randall feels neglected; Grimes mummy returns.

An ant-sized arsonist named Jerry flees Mark's custody, escaping up Twayne's nostril. A miniaturized Leonard, Grimes and Mark must track Jerry through Twayne's body to bring him to justice.

With the big company intramural football game around the corner, everyone starts getting nervous about the lineup -- Mark is a wonderful team player, but a terrible actual player. When Randall demonstrates the power of his recently replaced arm, he is given a job at the D.O.I. as the team's ringer.

In honor of Twayne's 10-year anniversary of running the D.O.I., Callie and the crew throw him a Roast. But when Mark's attempt at edgy humor goes too far, Twayne quits, leaving Mark in charge. Before his first day as boss is up, Mark makes a management mistake so catastrophic that it almost destroys New York City.

Mark becomes conflicted about his relationship with Callie. 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.

When the country's biggest pop star (Lady Hoo-Ha) turns into a zombie, millions of her devoted fans follow suit; Mark befriends one of the new zombies and Randall is forced to deal with his jealousy issues.

After being bitten by a rabid Bat-Boy, Mark becomes a masked crimefighter; Mark wages war against New York's criminals and their catlike leader with the help of his loyal sidekick, Koala Man.

Mark chooses April Fool's Day to ask Callie to take their relationship to the next level, but his romantic gesture is threatened when Callie's vengeful ex-boyfriend returns to win her back; Leonard tries to redeem a winning lottery ticket.