Helen and the children have gone on holiday, leaving Brittas home alone. Gavin's former girlfriend Jennifer returns, intent on reconciling, which causes a rift in his relationship with Tim, but then they discover that Jen has escaped from a mental institution with a case of explosives. Meanwhile, participating in Energy Saving Week, Colin has created a generator powered by the centre's 'waste material'; Jen attaches Brittas to the generator and he is electrocuted.