In the clearing behind her home, six-year-old Clare Abshire encounters 36-year-old time traveler Henry DeTamble for the first time. Fourteen years later, an unexpected reunion a the library gives Henry the opportunity to meet Clare.

After meeting her soulmate at age six, Clare laments a linear lifetime defined by waiting for Henry's unpredictable appearances. Meanwhile, an incident at a high school party finds a distraught teenage Clare turning to Henry for help.

Clare invites Henry to a dinner party, but when it's crashed by another Henry, secrets are spilled. Meanwhile, Clare tries to make her 18th birthday perfect.

Henry is finally able to get to know Clare's family better when he visits her childhood home for the first time. Henry and Gomez's friendship isn't going as they imagined.

As his wedding with Clare approaches, an increasingly stressed Henry finds unexpected solace in his estranged father.