Caroline and Gillian become unexpectedly close when Alan and Celia go missing all night during a thunderstorm. Robbie does what he can to help find them, and John finds out that Caroline's been seeing someone else.

Alan finds it hard to choose his best man. Caroline and Gillian discover they were born on the same day. Their respective birthday celebrations descend into emotional chaos when Caroline and Kate are outed by John.

Gillian and Robbie grow closer while Alan calls the wedding off, in an emotional conclusion to the series. But can Celia rise to the occasion, face her demons and get Alan back?