With the latest case of a murdered bail bondsman, Beckett discovers that Castle’s wild imagination and theories may be on the mark. Beckett’s ex-partner makes a surprise arrival and Castle is forced to watch the two reminisce and engage in a little romance.

Cal tries to thwart a bank robbery from the inside by forcing his way into the gang, and tries to talk one of the robbers out of seeking revenge for the bank erroneously foreclosing on his home.

When Jane’s shady brother-in-law (Kevin Rankin) comes to town and becomes a suspect in a murder investigation, Jane is forced to help him.

The story alternates to the Fringe Team “over here” where they investigate a mystifying case that people are discovered in a trance-like state that ultimately leads to their death. The unlikely suspect: a mysterious box. As Peter and Walter collaborate to study its properties, alternate Olivia presses on and turns up the heat on an unsuspecting Peter. Meanwhile, key information about the future is revealed when Walter and Nina meet at Massive Dynamic for the emotional reading of the last will and testament of William Bell.

Gloria decides to honor her late grandmother by cooking more traditional Colombian meals; Claire finds out Alex is interested in a boy; Mitchell’s aversion to public displays of affection causes an argument.

Mike and Frankie must decide whether to attend Axl’s football game or Sue’s first cross-country meet; after raking the yard, Brick wants to set the leaves free in the forest.