Spain, 1950s. Montse's agoraphobia keeps her locked in a sinister apartment in Madrid and her only link to reality is the little sister she lost her youth raising. But one day, a reckless young neighbor, Carlos, falls down the stairwell and drags himself to their door. Someone has entered the shrew's nest... perhaps he'll never leave.
1950s Madrid: The agoraphobic Montse raised her now 18 y.o. kid sister. The upstairs neighbor falls down the stairs and breaks a leg. The crazy Montse takes him in.