In the fourth episode, Dan takes his Behavioural Unit on a historical school trip with desperate hopes of becoming a 'bright light' his troubled kids can follow. Jo goes undercover to avoid government detection, obviously, and Brian has a mysterious secret passion.

In the series finale, Dan is caught in a race against the clock to prove his credentials as a dad, but a terrifying figure from his past surfaces to seek revenge. Brian decides to call time on modern 'feral' dating and Jo must decide who she really is.