Season 3, Episode 18

When Adam and Cassie embark on a relaxing day-trip to the nature park, they spot Charley with a mystery girl. Back at Solar Blue, he's evasive about his movements, and for the next week or so, he continually makes up excuses about his whereabouts. Cassie immediately jumps to the conclusion that Charley is cheating on Loren. Her suspicions are confirmed when Adam and Guy spot him with the same mystery girl at a café. Cassie finally snaps and accuses Charley of lying to them all and cheating on Loren. Shocked and upset, Charley storms off. After meeting Loren on the beach, explanations are in order. Back at the house, Charley confesses what has really been happening. Ellie, the mystery girl, is actually his sister. She's run away from school and Charley's been trying to help her. The kids are embarrassed at the lack of trust and respect they've shown Charley. They realise that even when all the evidence suggests otherwise - a friend is a friend - and that's pretty much all that matters.