Zack, convinced that Jez is not his dad, undertakes a DNA test to confirm his suspicions. Josh's increasingly erratic behaviour forces Tom to seek professional help. Elsewhere, Matt goes on the warpath when he fears he could lose Martha.

On the day of the fun run Jez's life starts to unravel as his star athlete, Mercedes, makes a huge error of judgement and Sian admits her true feelings about their relationship. Elsewhere, relationships are tense as Trudi makes a decision about Finn, and Grantly returns to work barely a week after the loss of his wife.