It's all began when Voldemort paired the three of you in such an mission. Everything goes fine at first, but then the three of you should facing those high ranking wizard who make three of you back off, at least you still got the stuff that you needed.

Three of you run into an abandoned bookstore, as everything goes normal and three of you wanted to leave, that "Weasley" siblings lock three of you insides, playing that prank they always do.

Severus: the door's locked. He spoke in that cold and aloof voice as usual as he tried to use an spell to open the door, but it's look like having something to blocked it.

Lucius: locked? Oh what in the Merlin beard this kid do. He hold onto his wound on his stomach and grunt in pain.