While on a trip to Minnesota, Ted and Barney try anything to make Marshall laugh. Marshall runs into an old nemesis from high school.

Cal investigates a deadly traffic accident caused by three high school students on a joy ride, and stumbles onto something much bigger.

Phil and Claire pressure Alex to ease back on her school work, but begin to worry about their own intellectual drives. Jay is upset when Gloria tries to befriend a new couple, and Mitchell runs into an old female flame.

Mike freezes Frankie out because he can’t fathom how she inadvertently paid $200 for a small bottle of eye cream that she thought was priced at $20.
Meanwhile, Axl’s fathering techniques are put to the test when he has to take care of a mechanical infant doll for health class, and Sue and Brick desperately search for a way to fix a hole that they caused in Sue’s bedroom wall.

Alicia’s law firm tries to turn a client’s son against his girlfriend when both are accused of murder. Alicia faces a tough decision.

Castle and Beckett investigate the murder of the owner of a historic magic shop found dead in a Houdini’s water torture tank. Meanwhile, Lanie and Esposito are trying to keep their relationship secret and Castle ends his relationship with Gina.

Emily seeks Cal’s help for her friend who is worried about her dad, who has been in a psychiatric facility for 5 years. Cal is immediately suspicious of the facility and puts his own sanity on the line when he gets himself committed so that he can work the case from the inside.