Waltz with Bashir by Ari Folman
One night at a bar, an old friend tells director Ari about a recurring nightmare in which he is chased by 26 vicious dogs. Every night, the same number of beasts. The two men conclude that there's a connection between the dream and their Israeli Army mission in the first Lebanon War of the early eighties.
Ari is surprised that he can't remember a thing about that period of his life anymore. Intrigued by this riddle, he decides to meet and interview old friends and comrades around the world. He needs to discover the truth about that time and about himself. As Ari delves deeper and deeper into mystery, his memory begins to creep up in surreal images. These recollections accumulate until, one day, Ari recalls Sabra and Shatila, and the terrible truth of what happened there is uncovered...