A scientist (Robert Flemyng) creates a creature (Wanda Ventham) that changes between a giant moth and a beautiful woman who pretends to be his daughter. As she goes around killing men for their blood, a policeman (Peter Cushing) is on their trail with his daughter (Vanessa Howard). There are better British horror films from the late 1960's and this has echoes of the earlier and better Hammer film The Reptile.