Bay is shocked to meet her biological father (Gilles Marini) at her school's art show, and then she introduces him to her parents and Daphne. Meanwhile, Daphne opens up to Emmett regarding her feelings about him, forcing him to make a difficult decision.

Bay believes she's uncovered her birth father's identity online, so she asks Daphne and Emmett to accompany her when she meets him. Meanwhile, John and Kathryn suspect Regina is to blame for the hospital's recent actions regarding their lawsuit.

Regina pleads with Daphne to keep her secret about what was in the guitar case, but soon the hospital board reveals info that forces Regina to spill everything. Meanwhile, Bay and Emmett's bond intensifies.

The trial involving the hospital's error gets under way. Meanwhile, Bay tries to return the cash she secretly took from John; Daphne and Jeff's relationship encounters obstacles; and Toby starts a new band.

Kathryn and John insist on having Ty over for dinner after they learn that Bay has been seeing him secretly. Elsewhere, Toby asks Daphne and Emmett to help him win a poker game, which puts Daphne in an uncomfortable position.

Bay and Daphne receive cars from John and Kathryn on their birthday, but Daphne is uncomfortable accepting such a lavish present. Meanwhile, Regina stops hiding out at Melody's place; and Bay and Emmett's secret romance continues to flourish.

Daphne struggles to keep up with a cooking class at Buckner Hall. Elsewhere, Bay and Emmett grow close while looking for clues about Bay's biological father; and Toby and Wilke try to break into school to swipe a test.

Bay fails to dazzle Melody with her American Sign Language skills. Elsewhere, Kathryn contemplates writing a book about her baby-swap experience; Daphne befriends an old pal of Bay's; and Wilke and Toby seek to make a profit by selling phony IDs.

Kathryn's mother visits the family and forms a bond with Daphne, yet Daphne still feels a strong connection with where she was raised. Meanwhile, Bay and Regina look into Angelo's disappearance; and Toby realizes he can only please Simone if he changes.

Things don't go well at Regina's art show, where Emmett's parents get into a big fight. Meanwhile, Kathryn's latest actions may jeopardize the lawsuit against the hospital; and Daphne feels caught in the middle regarding her two schools.

Bay must testify in Emmett's custody case, and Emmett's actions threaten to end their relationship. Elsewhere, a nervous Daphne prepares for a basketball tournament between her current and former teams; and Kathryn has a meeting with a New York editor.

The Carlton prom gets underway, and Travis tags along with Daphne and Wilke, while Emmett feels the weight of the secret he's keeping from Bay. Elsewhere, Angelo resurfaces; and Kathryn and John's lawyer crosses a line.

Bay returns from a trip abroad with a new boyfriend, but she must face issues from her past concerning Emmett and Angelo. Meanwhile, Daphne seeks employment help from Kathryn; and Regina impulsively makes a big decision.

Regina and Angelo face repercussions from their marriage. Meanwhile, Bay meets a fellow street artist; Daphne and Emmett enter their zombie movie in a film festival; and John's baseball record is in jeopardy of being broken.

Daphne causes a huge mishap at the restaurant, and she grows closer with her boss in the aftermath. Elsewhere, Bay manipulates a situation with her two dads to get what she wants; and Kathryn is envious of the attention an interviewer showers on Regina.

Emmett meets a girl who's a fellow motorcycle enthusiast. Meanwhile, John is enraged when his car wash gets tagged; and Kathryn slyly finds a way to get Toby to stop moping around the house.

Daphne struggles to decipher Jeff's signals. Elsewhere, Bay and Zarra try to find out who's ruining their street art.

John and Kathryn invite Alex to a family dinner, but Bay leaves during the meal to answer Zarra's plea for help. Meanwhile, a coworker asks Daphne to lie to Jeff; Toby grows closer with Nikki; and Regina reaches out to Patrick.

In the first-season finale, the trial ends with a surprising outcome. Meanwhile, Bay leaves with Zarra and doesn't inform anyone; and Daphne and Jeff's romance is revealed.

The Kennish and Vasquez families rally to support a loved one who is in critical condition. Amid the emotion, blame is placed, decisions must be made and lives are forever changed.

Intent on making their relationship work, Bay surprises Emmett with a visit to Los Angeles while he’s shooting his first big class project. Daphne is distraught with her performance in school and the idea of letting Bay and her family down. Kathryn and Toby get the chance to have their musical produced. Meanwhile, Regina is shocked by Eric’s reaction to a buyout offer on the coffeeshop.

Bay is excited to hold her first art show. Daphne interviews for an internship that would bring her closer to Quinn, causing friction with Mingo.

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.

Daphne leads her classmates in a protest against the closing of their school, and Bay's efforts to join them are met with resistance. The episode is presented entirely through American Sign Language.

A look at what would have happened if Regina had revealed the switch when she first uncovered it finds both girls being raised by the Kennishes: Daphne has a cochlear implant and is spoiled and manipulative, while Bay's a top scholar who overcompensates.