Naomi and Charlotte, Sam and Cooper
Naomi's medical license is jeopardized when it is learned that there were some switched embryos implanted in the wrong moms.
To make matters worse, one of the moms, Amelia, used the last of her dead husband's sperm to get Zoe pregnant. No do-overs there.
But Zoe wants to terminate and start over, while Amelia threatens to carry Zoe's child through to term and then keep it.
The doctors bring in Duncan the lawyer, who recommends paying them off. The moms agree in the end to carry the babies to term and switch.
The mess-up doesn't effect William's offer of Charlotte's job - he doesn't care about the mistake, and still wants Naomi. Not Charlotte.
Charlotte is fighting for her job, but she's done with Cooper, even when he tells her Violet is getting together with Pete, and so he's finally free to focus on Charlotte.
After William tells Charlotte she's fired, though, she rethinks how she just dismissed Coop.
Sam finally admits his love for Naomi. But she doesn't reciprocate, and takes William's offer to leave Oceanside.
Dell is the fall guy for Naomi's mistake, whether or not he was the reason for the mix-up. He's benched from practicing.
Heather comes back, high, and offering Betsy back ... for $10,000. Sam gives Dell the money, and when Heather returns with Betsy, he threatens to call the cops. He doesn't give the money to Heather, who bolts.
Noah's wife Morgan is back, ready to deliver the baby, and reads the chemistry between Addison and Noah immediately.
So Noah decides to tell Morgan of the feelings he has for Addison so that they can be together, but Addison blocks him from doing it.
However, she doesn't block him from almost consummating their cheating, as they begin to hook up ... just as Morgan's going into labor.
Addison is unable to deliver the baby in the aftermath of that near-miss, and makes Dell deliver Noah and Morgan's baby.
In the scary meantime, Katie, the delusional patient who lost her baby in utero a few episodes ago, is back, and off the meds.
Violet, Pete and Sheldon
Pete decides to follow Sheldon's lead and tells Violet that he should have fought for her, that he wants her, and the baby, and that he loves her.
Violet pushes him away.
As Pete and Sheldon point out later, together, Violet is pretty much unable to realize happy when presented with it. But hormones help Violet realize that she could indeed learn how to be happy, and with Pete.
However, moments after Violet basks in her future happiness with Pete, Katie shows up at her door with a syringe full of some paralyzing agent and a medical kit.
She's rescuing "her" baby from Violet's body. It's disturbing as she readies to literally cut Violet open on the floor after stabbing her with a needle that has her unable to move from the neck down.
Cooper almost walks in to stop this, but is called away by Charlotte, crying that she lost her job.