Schoolgirls in Chains (1973) 
This fairly enjoyable and sleazy little exploitationer is centered around two brothers who kidnap young girls and keep them locked up in their basement under the control and influence of their domineering mother. One brother is a simpleton who sees the girls as nothing but playmates and subjects them to various torturous games - playing doctor will never be the same again - whilst the other brother is more aloof and absorbed with his 'mommy issues'.
Whilst an exploitationer at heart, the film is often quite dark and brooding with lingering close-ups on the girls' facial expressions as they undergo and witness the various torturous shenanigans the brothers deploy onto them and that of their fellow captees. The low budget adds to the gritty mood and despite the twist element at the end, which becomes increasingly more obvious as the film progresses, this was an interesting and original enough experience to engage me throughout...
...let's hope the same can be said about the bulk of the other films I've still to see on this list.
