Clare (Rachel McAdams) has been in love with Henry (Eric Bana) her entire life. She believes they are destined to be together, even though she never knows when they will be separated: because Henry is a cheeky time traveler - cursed with a rare genetic anomaly that causes him to live his life on a shifting timeline, skipping back and forth through the years with no control. Despite the fact that Henry's travels force them apart with no warning, and never knowing when they will be reunited, Clare desperately tries to build a life with her true love.