It is a doozy of a set-up: the telltale digits, the amnesiac at large. The unfocused dread that Jennifer feels will linger to the end. But to call "Turn of Mind" a thriller - or a chronicle of illness, or saga of friendship, for that matter - would confine it to a genre it transcends. This is a portrait of an unstable mind, an expansive, expertly wrought imagining of memory's failures and potential.