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 at the library where he works gives Henry the opportunity to meet Clare and their love story begins... again.

After a rocky "first" meeting, Henry and Clare attempt to reset with a second date, but she still struggles to rectify this version of Henry with the man she's known - and loved - all her life. To help her better understand the difference between this 28-year-old and the man she'll help him become, Henry takes Clare back to the most formative moment of his childhood.

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 hosts a couples' dinner party to introduce Henry to her roommate Charisse and best friend Gomez, but when it's crashed by another Henry and his girlfriend Ingrid, deeply held secrets are revealed. Clare remains determined to make her 18th birthday and fated 152nd meeting with Henry in the clearing unforgettable.

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.