Samir is a young Palestinian boy who wishes for anything to happen — a bombing, an accident in the city square, anything — so that he won't have to go to the Israeli hospital to have surgery on his leg. Nothing occurs, though, and Samir soon finds himself in a hospital bed sharing a room with four other children each of whom has his/her own illnesses and troubles. He experiences many different emotions regarding his new friends who are from the nation that Samir blames for the conflict that killed his brother.
It is Yonatan, a boy with his arm in a metal cast and his nose always in an Astronomy book, in particular who captures his interest, speaking to Samir only at night once the other children have fallen asleep. He promises Samir that when Samir has had his surgery he will take him to Mars. How, Samir doesn't know, but in the quiet of the night the two boys plan a trip to the distant planet.
It is on this wondrous computer-generated trip with Yonatan that Samir begins to understand, and heal from, his brother Fadi's death. A trip where Samir can look at his world — a world of Palestinians and Israelis, sick people and healthy people — and see how simple it all really is, and how alike everyone really is.