In this episode, an unwelcome surprise birthday party for Henry inspires him to go out on the ‘lash' to prove that he's still as fit as he was in his youth. But a misjudged late-night dip in the sea seemingly leaves both him and Charles very much worse for wear. As their symptoms deteriorate, they ultimately end up in hospital, with Henry finding the modern day ‘customer'-orientated NHS too much to bear. Meanwhile, Charles' efforts to distract Margaret from the romantic advances of the suave Dr. Cranmore land him in an isolation ward, and it transpires Cath's new fascination with all things medieval could have a lot to answer for.

A regular Northern Soul night at a local club is providing Henry with the perfect opportunity to let his hair down – and in true Brighton style that means ‘anything goes'. But by persuading Margaret and Charles to join him, it looks like the fun will be short-lived when he lands the former with an unwanted admirer, and the latter in a dangerous liaison with an ex. When a suspicious Charles then overhears a conversation between Henry and Margaret suggesting they are now an item, it looks like their friendship could be finished. Things go from bad to worse when Cath, determined to show she knows how to have fun, railroads Amaya into hosting a house party, which quickly gets out of control, ruins Jeremy's big surprise and finds Henry in a compromising position with the police.