The lives of several people, including some who share the same birthday, prove to be connected in surprising ways.
Kate gets support from her new boyfriend as she struggles to lose weight; Beth questions the motives of Randall's biological father, William; marriage and raising three children begin to take a toll on Rebecca and Jack.
Rebecca unexpectedly encounters Randall's biological father; Kevin decides to move to New York, expecting that his sister, Kate, will join him; Jack and Rebecca bring their babies home; Rebecca tries to reconnect with her adopted child.
Jake and Rebecca take Kevin, Kate and Randall to the community swimming pool; Kevin auditions for his first Broadway play; Toby bumps into his ex-wife at a restaurant; William is mistaken as a loiterer.
Jack and Rebecca argue about the idea of starting a family; the story behind the family's love for the Pittsburgh Steelers is revealed; Kevin discovers that the script for his part in the play is relevant to his own life.
Kate interviews for a new job; Randall doubts his career path; Kevin and Olivia's relationship moves in a different direction; Rebecca and Jack are conflicted on what to do when Randall tests as a gifted child.
William unexpectedly reveals a secret to Beth when they are together; Rebecca and Jack admit there's a distance between them; Toby strays from his diet.
An unforeseen detour interrupts Jack, Rebecca and the kids' trip to their traditional Thanksgiving dinner; Kate makes life-altering decisions; Olivia accompanies Kevin to Randall's house; Randall learns a heartbreaking secret.
Kate, Kevin and Randall head to their family's cabin after a chaotic Thanksgiving; angry Randall looks to Jack for comfort and an explanation; Olivia's words drive a wedge between Kate and Kevin.
When Kate comes down with appendicitis on Christmas Eve, the Pearsons take her to the hospital, where they run into Dr. K, who they realize needs their support; Kevin celebrates Hanukkah with Sloane's family.
Kate wrestles with her feelings following Toby's heart attack; Randall has to get used to his father's relationship with Jesse; Jack and Rebecca must find a home that can accommodate their growing family when they find out they're having triplets.
With the birth of her triplets approaching, Rebecca forgets Jack's birthday; Dr. K struggles with the loss of his wife; Joe, the firefighter who brought baby Randall to the hospital, tries to save his marriage.
Jack and Rebecca try to throw Kate, Kevin and Randall three separate birthday parties; Randall has trouble making time for William; Kevin makes a decision regarding his romantic life; things take a turn with Kate's gastric bypass.
Toby throws a wrench in Kate's weight-loss journey; Randall struggles to accept his father's failing health; Miguel and Shelly have terrible news for Jack and Rebecca; Rebecca receives a work opportunity; Kevin examines his romantic past.
Kevin stresses about the premiere of his play; Randall struggles under the pressure of his work and his ailing father; Rebecca and Jack's Valentine's Day doesn't go as planned; Toby and Kate decide to get to know each other's biggest secrets.
When Randall and William take a road trip to Memphis, Randall learns about his biological father's past.
The Pearson family gathers at Randall's for an unusual party; Kevin and Sophie's relationship deepens on the night of his play's premiere; Kate struggles to open up to Toby about her father's death; Rebecca leaves on tour with her band.