Rebecca makes a surprise visit to Randall's home where she encounters his biological father, William. Kevin anxiously decides to take the plunge and move to New York to pursue a Broadway job, with the expectation that his sister, Kate, will move with him. Toby is determined to get Kate out of Kevin's shadow. Jack and Rebecca take home their babies from the hospital and adjust to the new life of parenthood, while coping with the loss of their other child. Rebecca struggles to connect with their adopted child and searches for answers.

The Pearsons gather to celebrate their 40th birthday while musing about the day they were born.