The PCs Can't Swim

You and three of your friends are facing down the halls of a dungeon created by a dastardly mastermind. You know they have stolen something or have done something truly evil, and they must be stopped! But, you must get to them first. The problem is, you don’t feel as if you can do as much skills-wise as you used to. 

Huh. That’s funny, where did the whole menu of skills go, and your collection of magical items? Each one of you is now equipped with 1 useful item and the ability to do one special movement, which means in order to get through this dungeon, you all must work together!

This is a game meant for three or four PCs and one Dastardly Mastermind to build the dungeon and control the baddies