It's Halloween and Max Darwin is out trick-or-treating when he gets the call summoning him back to Bug Island. No sooner have Max and the Battle Bugs finished building the defensive watchtower on Howling Cliffs when it is attacked by cliff-dwelling geckos. Max and the bugs are trapped inside and, worse still, a squadron of Basilisk Lizards is approaching across the cove. Can Max break the siege and save the bugs from certain defeat?