A series of false alarms at a private school hinders 51’s ability to respond to legitimate emergencies. Kidd asks for ideas to surprise Severide on his birthday. Cruz and Brett rent out their extra room but get more than they bargained for.
The members of the BAU enjoy a Saturday off in vastly different ways. Rossi and Prentiss help Simmons assemble a new crib. Garcia leads a hacking competition. Reid strikes up a conversation with a woman named Maxine.
Mitchell learns a valuable life lesson when a former resident of the house shows up unexpectedly. The Dunphy's old neighbor-turned-tech-titan comes to visit with a big surprise for Phil. Manny's dad has a big opportunity for his son.
Bjorn faces a difficult decision. In search of new lands and old friends, Ubbe and Torvi leave Kattegat. Oleg’s plans for the invasion of Scandinavia are taking shape. King Harald is baffled by the origin of a mysterious raiding party.