Lena meets troubled teen Callie and asks her to temporarily move in with her family in the series premiere of this drama about a lesbian couple heading up a multiethnic family comprised of a biological son and a few adopted children.

Lena and Stef decide to let Brandon off the hook for running off with Callie to rescue Jude, but Mike disagrees and tensions flare. Brandon ends up grounded, but he makes plans to sneak away to see Talya while her parents are out of town. Jesus stops taking his medication to cover for his twin sister and the pills she stole, but he becomes easily agitated and gets into a fight with another kid at school. When a student is discovered with the pills, Callie becomes an instant suspect, and Mariana struggles with her mounting guilt over letting someone else take the fall for her actions. Meanwhile, a secret romance blossoms between Jesus and Mariana's best friend, Lexi. The Fosters make arrangements at home to ensure that Callie and Jude are more comfortable, but sharing their space may prove difficult for the Foster teens

The Fosters cope with a crowded house but when Mike suggests that Brandon come live with him, Stef argues that it's not Brandon's decision, resulting in a heated argument with her son. Meanwhile, Lexi and Jesus resolve to end their budding relationship but find that their attraction to one another may be too hard to resist. Callie openly disapproves of Mariana letting Jesus take the fall for stealing his pills but when Timothy, Callie's teacher, gives her an assignment to write about guilt in a journal, it drudges up her own dark secrets and a mysterious name from her past.

Mariana's quinceanera is coming up and Lena wants it to be the best. However, when a secret is revealed, it could end the party before it even starts. Lena's mom comes for a visit and Stef gives Brandon a pep talk on the rules of dating when he see's Talya and Callie getting more friendly.

When things between Jesus and Lexi get hot and heavy, they are forced to face the possible consequences of their actions. Meanwhile, Callie gets closer to Wyatt but Brandon has serious reservations about Callie dating a "bad boy". Stef and Lena learn that two of their close friends, Kelly and Jenna, are having major relationship trouble and it causes them to look at the lack of romance in their own lives. Kelly and Jenna's hip and educated son, Garret (played by real life slam poet Noah St. John), catches Mariana's eye and she becomes desperate to fit in with his cool, edgy crowd. Jude is bullied at school for being different.

The Fosters invite Ernesto and Sofia Rivera to dinner, and Stef worries that they will subjugate Jesus to views that disapprove of his non-traditional family. To make matters worse, Stef's conservative father, Frank, shows up and the family dinner threatens to turn into an all-out moral debate. Meanwhile, Callie attends a group therapy session for foster children and meets someone with a connection to her past - a past that will come back to haunt her. Wyatt holds a destructive party at his childhood home, which is under foreclosure, and Callie realizes he's much more hurt than he lets on. Mike shows up late to take Brandon to an important audition with a renowned piano teacher.

Feeling betrayed and angry, Jesus and Mariana get into a major fight. When Lexi's parents take measures to keep her away from Jesus, Lexi makes a desperate decision, which could have serious and lasting consequences for her and her family. Meanwhile, Lena urges Callie to participate during her weekly group therapy sessions. Callie is conflicted but she opens up to Brandon, who supports her as she confronts a painful memory from her past. Jude hopes to impress his new friend Connor, who comes over to work on a school project.

A visit from Lena's beautiful and sophisticated ex-girlfriend reveals a secret yearning Lena has hidden from Stef for the past ten years. Meanwhile, Brandon struggles to please his demanding new piano teacher and rebuffs an offer from Talya to reconnect. When an embarrassing video of Talya circulates around the school, Callie lends her support and urges Brandon cut her some slack. Mike's drinking and Stef's mounting concern do not go unnoticed at the precinct. Mariana and Jesus go to tell Ana to leave Mariana alone. The encounter with his birth mom and her desperate situation drive Jesus to take matters into his own hands, a move that could have dire consequences for the whole family.

While Lena tries to process the extent of Mariana and Jesus' lies, Stef and Mike head to Ana's to try and find Jesus. What they encounter lands someone in the hospital and changes the Foster family forever. While the family waits anxiously for news, tensions rise over the secrets the kids kept from Stef and Lena and even Brandon realizes he's to blame for covering for the twins. Callie has a heart-to-heart with Brandon to help him understand the perspective of a foster child and Brandon learns how Callie's mother died. Wyatt calls Callie on her growing bond with Brandon but Callie is all too familiar with the damage that could result from this kind of relationship.

Stef and Lena try to maintain calm when their parents descend on the Foster house for a very special celebration. Lena's dad, Stewart, has agreed to officiate the ceremony while her mother Dana and Stef's colorful, talkative mom Sharon, attempt to keep things civil while disagreeing on floral arrangements. Sharon tries to strong-arm Frank (Sam McMurray) into attending. Stef avoids telling Lena she plans to return to work as soon as she is cleared. Meanwhile, when Callie's case against Liam boils down to her word against his, she must decide whether or not to lie in order to get some justice out of the situation. Callie and Jude get some news they've been hoping for, but Callie makes an emotional slip that could destroy any chance they finally have at happiness.

The repercussions of Callie's decision to run away impact every member of the Foster family, including newlyweds Stef and Lena, who had offered to adopt the troubled teen. Both Jude and Brandon struggle with their own personal guilt about her running away. Mariana inadvertently discovers the whole story about Lexi's upcoming trip to Honduras.

Callie meets Rita Hendricks, a woman who works in the foster care system, and it's clear it will take Callie some time to adjust to Rita's no-nonsense guidance. Brandon comes clean about the reason Callie ran away and, unbeknownst to Stef and Lena, he sets out to track her down. Meanwhile, Mariana volunteers to help with the school play in order to impress a cute boy, but when she gets paired up with an old "friend", it could spell trouble. Jesus' meds are having concerning side effects, and he's desperate to find an alternative to taking the pills. Mike suggests he participate in contact sports to help relieve his aggression, and Jesus tries out for the wrestling team.

When Callie's probation officer learns of Callie and Brandon's relationship, it poses serious consequences for both teens. Stef and Lena are forced to take more severe measures to keep them apart. Meanwhile, Stef returns to work, leaving Lena riddled with anxiety. Jesus bonds with his wrestling team but Lena's reaction to a hazing tradition threatens to shake the hard-earned respect of his teammates. Kelsey's jealousy over Mariana's growing attraction to Chase (guest star Garrett Clayton "Teen Beach Movie") leads Kelsey to expose some nasty secrets from Mariana's past. Fearing Callie's actions will get them both sent away from the Fosters' home, Jude makes preparations.

There are possibilities of someone being pregnant. She speaks with her gynecologist to know if she's still qualified to become pregnant. The issue here is that she hasn't spoken with her partner about it. Jesus tries to drop weight for wrestling, and he and Emma flirt with each other. Meanwhile, Rita opens up to Callie about her past: she cheated on her ex-husband.The Fosters visit Callie and learn she may not return with them. Callie shares a secret with one of her housemates, but events are turned upside down. Stef and Lena discuss with Jude about the option of adopting him without Callie. Stef and Lena are caught off guard by something Stef's dad Frank does.

Recent events bring up painful memories for Callie and Jude and make Callie question what is most important to her. Stef is flustered by a discovery about Lena and Mike is troubled by new developments in the shooting investigation. Meanwhile, Jesus' long distance relationship with Lexi is complicated by his growing bond with his wrestling teammate, Emma.

Callie makes a life-changing leap in order to better her future and earn back the trust of her loved ones. Brandon makes a move of his own, much to Callie's disappointment. Stef is called to testify in Mike's case and is faced with a decision that could mean losing her job. Meanwhile, Jude unravels a mysterious message, and Mariana makes a bold move to win Chase's attention.

Callie finds a way to use her photography skills for a good cause, but it unintentionally leads to trouble for someone she cares about. In an effort to clear his own conscience, Brandon makes a deal with an unscrupulous classmate and finds himself in over his head. Mariana deals with the unwelcome consequences of her stunt to earn Chase's affection, and tension comes to a head between Jesus and Emma during a wrestling match. Meanwhile, Stef and Lena contemplate another big step for their family.

Jesus feels the pressure to make a difficult choice and his inability to focus poses a challenge during an important wrestling match. Callie suspects Brandon has gotten himself into a bad situation and struggles with the decision to protect him at the cost of another friend's reputation. Stef and Lena reveal a caveat to Callie and Jude's adoption and the siblings must decide whether they want to face their past or move on with their new lives. Mariana gets an unsettling glimpse into her friend Zac's home life when his mom shows up.

An encounter with her father leaves Callie conflicted about her future and worried about the effect the reunion will have on Jude. Meanwhile, Jesus struggles to maintain his focus at school without his ADHD medication, and Mariana gets an unexpected invitation from Zac's mom. Lena and Stef come to a major decision with the help of a good friend.

As the high school's Winter Ball approaches, Mariana and Jesus fret about dates and a surprise nomination for Winter Queen raises suspicions. Zac's mom shows up at school to talk to Lena. An old friend pays a visit to Callie wanting to make amends, and Brandon feels threatened. But a past mistake could cause Brandon to lose Callie for good. Ana returns with unsettling news for Stef.

Stef and Mike are faced with the repercussions of a shocking revelation, and the fallout could destroy lives and relationships. Callie contemplates her upcoming adoption and Brandon's frustration leads him to make another regrettable decision. Mariana supports a friend with a difficult decision, and Jesus resolves to make a change for the better as he manages his ADHD. Jude gets asked out on a date.