Only child Julia Bechley finds her life turned-upside down when her father reveals that, over the course of his prize-winning career as a pioneering fertility doctor, he used his own genetic material to conceive upwards of dozens of children. Reeling from this explosive revelation, Julia discovers two new sisters – former best friend Edie Palmer and ex-Olympic athlete Roxy Doyle. As these three young women begin to embrace their new reality, Julia must figure out what life is like without her father by her side; Edie comes to grips with her burgeoning sexuality, as her marriage falters; and Roxy faces adulthood out of the spotlight. Against all odds, the three women will attempt to form a bond as sisters, even as they must welcome a tidal wave of new siblings into their rapidly expanding family.
Julia is haunted by her new reality, while Roxy embraces it by spending quality time with Leon. As Edie and Tim prepare for their trial, Tim notices interactions between Edie and the prosecutor, Amanda, that make him uneasy. Meanwhile, Dr. Isaac Abadi steps up to the plate at the clinic.
Julia's dirty laundry is aired for the world to see when a video goes viral and she is forced to team up with Isaac to combat the situation. As Roxy forms a bond with 11-year old Izzy, who has some serious gymnastics potential, Edie meets with Dr. Bechley regarding his case. Meanwhile, just as the relationship between the sisters begins to grow stronger, a shocking new witness comes forward to testify in the trial.
The sisters meet a new sibling, restaurant owner Nate, who helps them secure one of the most exclusive reservations in New York. Unfortunately, the dinner doesn't go as planned and Julia is forced to apologize to Roxy and Edie for her missteps. Meanwhile, Edie and Tim discuss starting a family, but Edie is conflicted on where she stands, Dr. Bechley begins his volunteer work at a hospital, where he uncovers another Bechley baby and Roxy invests her time in training her gymnastics protégé, Izzy, while tensions with her parents rise
Julia is forced to make a drastic decision when she finds out that Isaac has been secretly working with Leon for advice on his current patients. Meanwhile, Roxy takes her new protégé back to her old gym, where she runs into old enemies from her gymnastics days, Tim is on high alert when Edie misses a family event to "work" all weekend and Julia steps back into the dating scene.
Another Bechley baby comes to the clinic looking for information about Leon and then invites her new family over for Shabbat to get to know them. Meanwhile, Julia is developing feelings for Donovan, but as the topic of children arises, they seem to disagree. Amanda suggests that she and Edie go on a weekend getaway, as Tim's suspicions grow deeper. In court, Edie catches Amanda off-guard getting a key piece of evidence dismissed. Dr. Isaac develops suspicions regarding Roxy's past and current drug usage, but when he confronts her, she gets defensive.
In an attempt to start a new tradition, Julia hosts Thanksgiving dinner for her ever-growing family, but things go awry when she invites both Leon and the new guy she's been seeing, and Roxy let's a new half-sibling tag along. Meanwhile, with Tim's parents in attendance, relentlessly homing in on the idea of children, Edie finds herself at a crossroads.
Julia enquires about her own fertility options and entrusts Dr. Isaac to help her explore possibilities. Meanwhile, Edie struggles to tell Tim the truth and Roxy deals with concerns from her family, old and new, regarding her drug usage.
Roxy is released from rehab and begins to make amends with those she hurt. In apologizing to Natalie, Roxy finds out that Izzy is now coached by Nick, which enables her to reveal the truth behind their relationship. Donovan decides it's time for Julia to meet his kids, but Julia quickly realizes teenagers are trickier to win over than she thought. Edie and Amanda's personal relationship blossoms, but Edie struggles to make a worthwhile deal for Leon's sentence.
Roxy takes her first steps in speaking out against Nick, but quickly realizes the hardships that come with going public, especially when her rival attempts to discredit her story. Julia, frustrated with the lack of knowledge about her family history, meets up with her mom's cousin who explains a whole other side to her mom she never knew. Worried she might get cold feet later down the line, Amanda challenges Edie to explore her sexuality. Meanwhile, Leon tries to convince Edie to work a pro-bono case for her half-brother.
Julia searches for more information about her mom, with added help from Nate. When Edie is granted approval to take on her half-brother's pro bono case, she realizes Tim might have had something to do with Chad's change of heart. Meanwhile, Amanda confronts Roxy with suspicions of witness tampering regarding Dr. Bechley's trial and the search for character witnesses continues.
The trial against Dr. Bechley begins with a powerful opening statement from the prosecution, leaving Leon scared and Tim wondering if Edie should rejoin the defense team. Tensions rise when Chad makes a threat to bring Edie and Amanda's affair to the judge's attention. Meanwhile, Julia gains the confidence to approach Donovan again about her desire for a family.