Tensions simmer at school when new boy Nick stands against Marcus for school president. Tim tries to help Marcus but, given previous form, is more likely to hinder the campaign. Operation Sabotage is in full swing back at MI5 as Tim offers Caitlin and her presumed-dead but now actually very much alive fiancé Portis some rather dubious relationship advice. New counsellor Owen makes an impression too, taking a particular shine to Judith.
They say you can't help who you fall for, but a woman in the Witness Protection Programme - really, Tim, really? The lovesick sleuth is asking for trouble and it falls to best bud Chris and ex-wife Judith to sort out the sticky situation. Marcus is an extraordinarily gifted child, master of many subjects and skills, except, we learn this week, riding a bike. Find out if the youngster perfects the pastime or risks experiencing the social stigma that unavoidably comes with stabilisers.
Marcus is obnoxiously bright, the kind of kid you imagine becoming a world leader, or, alternatively, criminal mastermind. After being sent on work experience, though, he develops a taste for retail. Meanwhile, considering his - to put it politely - unorthodox approach to his job, it's no surprise to learn that The Examiner's appraisal doesn't go to plan.
In an hour long Christmas special, the magic of Christmas has long been lost on Marcus and, when his party plans force the other kids to go on strike, he must make alternative arrangements. Meanwhile, 'tis not the season to be jolly if you're Portis. The agent's thoughts turn to revenge after he finds out about Tim and Caitlin having feelings for one another.