It is Day Four in camp as the Outsiders battle it out to see who will create the best apocalyptic society. Today, David Mitchell invites former Outsider, Lou Sanders, to help him judge the Energy Healing badge. Alan and Roisin invent 'Chase Therapy', while Guz and Judi create an alternative 'Rebirthing Therapy' - an experience that David never wants to repeat. David also challenges the six comedians to create a post-apocalyptic, urban utopia and compose an anthem to unite the camp. At the end of the day, David summons the teams to his HQ to review events and award badges for successfully completed challenges. The result leads to some hilarious moments and some unpredictable outcomes!