A Year in the Death of Jack Richards (2004)

Jack Richards, a professor in his 50's, has apparently gone mad over the supposed abduction of his daughter by a sinister cult. Wallowing in self-pity for years, he decides to commit suicide. However, the manner in which he decides to suicide is quite peculiar: he allows himself to be abducted by a cult, whose members treat him as their "king" for one year (he is given a castle, concubines, gifts, etc...), and then murder him as an atonement for their yearly sins.