MR. DO! is in a bit of a bind - again! This time, a pack of pesky unicorns is trampling the bricked hallways of his castle. Help MR. DO! rid his dwelling of these crafty, quick-changing (and deadly!) creatures with the skillful swing of a hammer. Sometimes a quick clobber to the head will do it. Or maybe a well-chosen brick knocked out from above. If you can't stop these critters, then break a hole in the floor to slow 'em down. It's up to you to know when to fight - or when to flee!