Special 50th issue! Five freaky monsters have just been caught and it's Mystery Inc. under the masks! What's going on? And what will happen when the gang winds up in the same prison as every single criminal they've ever foiled? This issue features tons of cameos by your all-time favorite Hanna-Barbera cartoon stars!
1. Big House Brouhaha (written by Dan Slott)
"Guest stars galore"