Callie thinks she's celebrating her 17th birthday with just the family, but Jude surprises her with a house party. Jude's surprise risks exposing both Callie's and Mariana's secrets when he innocently invites Rafael and Wyatt to attend. Meanwhile, Brandon's suspicions about AJ's behavior come to a head, and Mariana and Callie decide to buy a car together without telling their moms.

Brandon plays referee between the two stars of his show, Mariana and Mat. Callie testifies on behalf of Daphne in an effort to help her get her daughter back.

Lena is excited that her family is coming together to throw her a 70s-themed 40th birthday party. But, when Lena’s mom Dana shares her suspicions about Stewart’s behavior, it threatens to put a damper on the festivities. Convinced her former foster brother Kyle has been wrongly convicted of murder, Callie and Aaron try to track down a witness in the case. Mariana and her female STEAM club teammates compete for an invite to the Regional Robotics Competition. Meanwhile, Jude is hurt to discover that Connor came to town and didn’t tell him, and Brandon considers drastic measures to make extra money.

Sharon and Will return to the Adams Foster home with news that they are engaged. In an effort to come clean with Jesus, Emma writes him a letter but learns he is hiding a secret of his own. Meanwhile, Jude is teased at school when Lena organizes an LGBTQ-friendly sex ed class for students.

As Stef works longer hours in her new position, Lena feels overwhelmed trying to keep up with the complicated lives of their five teenagers in addition to the pressures of her own job. Jude, fed up with being bullied at school, resorts to bullying tactics of his own. Callie heads to Los Angeles with Aaron to visit his parents, who are struggling with Aaron being transgender.

Callie is torn with turning over a new leaf or supporting a cause that means a lot to her, while Jude and Taylor begin making gaming videos that earn them unwanted notoriety. Stef makes major headway in her case.

Brandon throws a party which turns south when secrets are revealed. Mariana and Jude try to convince the students to vote against their school going private.

Stef confronts her demons and finally comes clean to Lena about what’s been troubling her. Mariana and Emma find themselves going head to head, putting Poppy and Jesus in an awkward position.

One year later, the Adams Fosters comes together for some major celebrations.