Stash House (2012) on Netflix

A couple love their new house, bought for a steal out of a foreclosure. During their first visit they find illegal drugs stashed in the walls, and they realize this is not their dream house. As they are about to leave, suddenly their exit is blocked by a gun-wielding neighbor Spector and his accomplice. They come to realize the house is hiding more than drugs - it's the operation center for mass drug czar who is buried beneath the floorboards. On the run from the professional killers who want the drugs and evidence, the resourceful couple will need to turn the tables on their attackers to survive.