The film follows (Jim Carrey) and Clementine Kruczynski (Kate Winslet), whose relationship has soured.
As the memory erasure progresses, the film shifts inside Joel's mind. He revisits his past with Clementine in reverse chronological order , moving from recent arguments back to their initial, passionate attraction.
After a painful breakup, Joel discovers Clementine has used a service called Lacuna Inc. to erase all memories of him. Heartbroken, Joel decides to undergo the same procedure.