Starring Lior Ashkenazi and Knut Berger. In Hebrew, English, and German with English subtitles. Unrated.

A tightrope stretched between enemies is the narrow territory staked out by Walk on Water, a messily ambitious new film from Eytan Fox, the director of Yossi & Jagger.

The film stars Lior Ashkenazi, the reluctant groom in Late Marriage, as Eyal, an expert assassin who feels just about nothing while carrying out orders for the Mossad, or Israeli secret police. Eyal's cold-bloodedness is put to the test when his wife commits suicide and, refusing psychological help, he is reassigned to what he considers a "soft" assignment: shepherding a German tourist around Israel. In reality, the young Berliner, called Axel Himmelman (Knut Berger), is no ordinary traveller. His grandfather was a notorious SS bigwig, wanted by Israel for war crimes, and Eyal's avuncular Mossad boss (Gideon Shemer) figures that Axel might spill some beans while visiting his sister, Pia (Caroline Peters), who is penitently living on a kibbutz.

Homophobic, Arab-hating, antireligious, and cynical in the extreme, Eyal isn't a very convivial tour guide, and for all his elaborate spy-guy training, it takes him the better part of a week to figure out that Axel is gay. (He's pissed off that he wasn't told.) Nonetheless, the men have begun to bond. In fact, the tough agent barely even notices that Pia is, like, totally into him.

On the plus side, though, is very engaging cinematography from Tobias Hochstein-who wrings arresting images from the Dead Sea-and a slowly building sense of wonder at the idea that people can change. If Germany and Israel can be joined at the hip, as they are today, perhaps anyone can be joined at the heart.