Moderately successful TV actor Andrew 'Large' Largeman (Zach Braff), who has been in a lithium-induced daze for years, returns home to bury his suicidal mother and to rebuild bridges with his estranged psychiatrist father Gideon (Ian Holm).

By chance, Large meets bubbly compulsive liar Sam (Natalie Portman), whose effervescence and exuberance captivate the actor and gradually draw him out of his shell.

Her fearlessness in the face of almost inevitable heartache gives Large the courage to embrace life again and to open his wounded heart to love.