Sam, Cooper, Charlotte and Amelia team up to save the life of their friend Pete after he suffers a heart attack, while Violet, who was in the middle of leaving Pete and LA, is nowhere to be found. Meanwhile, Addison's desire to have a baby leads her to see Jake Reilly, her recent mystery man, in a most surprising place, and Sheldon tries to help Amelia in her battle with alcohol.
The Oceanside Wellness doctors interview potential replacements for Naomi, including Jake Reilly, and no one understands Addison's resistance to hiring him; Cooper breaks the law and crosses his wife, Charlotte, in an effort to get cord blood for a young, sick patient; and Pete directs his post-heart attack frustrations towards Violet.
Addison and Jake work with a patient who wants to have a baby even though she doesn't have a uterus; Amelia, back in AA and seemingly back on track, treats a Parkinson's Disease patient who habitually cheats on her husband; Violet, struggling to be a stay-at-home mom, attends a mommy group and finds it's not for her; and Cooper receives the surprise of his life.
Cooper receives the surprise of his life when a woman from his past arrives at the practice; Addison consults her patient, Jodi, who is eight and half months pregnant and suffering from severe memory loss after a traumatic car accident; and Sheldon and Violet clash when their patient, Jodi's husband, Zach, considers leaving his wife and taking the baby with him.
Addison begins in vitro fertilization treatments with Jake's help, unbeknownst to Sam, Amelia is deeply conflicted when her terminally-ill friend, Michelle, asks her assistance in her suicide, and Sam and Violet contend with a patient who refuses his anti-psychotic medication.
Charlotte's painful memories of a horrible tragedy are triggered as Amelia continues her downward spiral; Addison takes one step closer to motherhood when she finally chooses a sperm donor; Cooper faces a difficult decision when he realizes his patient's parents have been drugging their son in an effort to control his supposed ADHD; and Pete's trust issues prevent him from repairing his fragile relationship with Violet.
Amelia's drug addiction spins further out of control as she plays hooky from work with a new fling, starts writing pill prescriptions for herself, and has a run-in with the cops; Addison and Jake are at odds when they must make the impossible choice between donating their patient's organs or saving the life of her healthy, unborn baby; Violet begins working at Seaside Wellness again, and Cooper, Charlotte and Mason begin to form a family bond, much to Erica's chagrin.
The Seaside Wellness group stages an intervention for a defensive and volatile Amelia, who has resurfaced after disappearing on a 12-day drug binge with her boyfriend, Ryan. During the intervention, Amelia mercilessly attacks her friends one-by-one, and Addison, in particular, has trouble seeing her sister-in-law in her present condition.
Amelia makes the hard decision to enter a rehab facility, and finds strength in an 18 year-old girl, as they both go through the painful detox process. Meanwhile, Cooper's strengthening bond with his son is tested by his allegiance to a patient in need, Pete and Violet's marriage reaches a tipping point, and Addison collapses from her rigorous fertility treatments.
Cooper struggles with whether or not to punish Mason after he catches him stealing; Pete and Violet find it hard to split time with Lucas now that they're living apart; Addison makes changes in her home life to prepare for a potential new baby; Violet and Jake work with two women and a man involved in a polyamorous triad; meanwhile Amelia returns to the practice and realizes how badly she hurt Sheldon when she was abusing drugs.
Pete, Violet, Sam and Addison adjust to their new, singles lives in different ways. Addison questions how much she wants a baby and confides in Jake, Violet considers an offer to go on a date with a young, hot paramedic, and Sam and Pete have a bachelors' night at a local bar. Meanwhile, Charlotte faces a personal, ethical dilemma when Amelia uncovers a secret about Mason's mom, Erica, and Sheldon refuses to bend to the pressure when an old friend from the police force wants him to rubber stamp a fellow cop suffering from PTSD.
Just as Violet's personal life takes a turn for the better with Scott, the paramedic, Joanna (the abused woman she met at the airport months earlier) arrives in need of urgent medical attention, being both pregnant and badly beaten; Cooper, Charlotte and Amelia all counsel Erica on the toughest decision of her life; and Addison and Jake meet with potential surrogates.
Sheldon treats a married Army veteran who was sexually assaulted. Jake and Addison drive to Palm Springs for a medical conference. Erica and Mason are involved in a car accident when Erica's condition worsens and she has a seizure while driving. Pete becomes angry and jealous when he catches Violet kissing Scott. Sam has to bail his sister out of jail.
Sam finds his estranged sister, Corinne, in jail, heavily medicated and near-catatonic, and brings her to Sheldon for help; Erica begins secret treatments for her cancer and refuses to let Cooper and Charlotte tell Mason; Cooper, Pete and Addison treat the baby of a drug addict; and things between Violet and Scott continue to heat up in the bedroom.