One Monday afternoon, around three o'clock, pond supplies salesman Selwyn Robby arrives home towing the Toogood Aquatics exhibition caravan and orders his like-wife, Imogen 'Ginny' Dare, to get into the car. He's taking her on a little holiday, he says. To Wales.

So begins their road trip west via ponds, pitstops, and blasts from Selwyn's past. But it's a fishy business towing this caravan with its saucy mermaid curtains, fully stocked bar, and the words 'For your pondlife and beyond' in the slanted red font favoured by Pound shops. And Ginny must untangle the pondweed to get to the bottom of it, even it does mean unearthing her own murky past to find out.