Engineer Quiller has become rich by selling his completely indestructible shop-window glass to jeweleries around the world. But this got him lots of enemies too: the insurance agencies, who've lost hundreds of customers, and the burglarers. When he temporarily looses his memory and voice in an accident, of all people, a family of thieves finds and cares for him - believing he's a pocket-picker. Things get complicated when he falls in love with his host Tilli.