Needing to pay their electric bill, Bay and Daphne throw a "lights on" party at their apartment, but things go awry when rowdy, uninvited guests get out of control.

In the emotional 90-minute series finale of the award-winning drama, Kathryn becomes nostalgic when she realizes that it's been five years since the switch was discovered and the two families started living together. As she searches for memories, Kathryn discovers a long buried family secret - stretching all the way back to the switch - that changes everything. Daphne competes against Mingo for a six-week paid internship in sports medicine. Bay is celebrated for her tattoo work in a magazine spread, but her struggle to prove herself as an artist to John threatens to destroy their relationship. Toby meets Amelia, a young woman with Down Syndrome who changes his perception about his son's future. Melody, Emmett and Travis make some major decisions about their lives, and Regina takes a chance on love.