An eccentric, forthright, and often likable excursion into sixth-century Welsh mythology, combining animation and live action - assisted, inevitably, by lottery funding through the Arts Council of Wales.

Three teenagers, Lleu (Matthew Rhys), Rhiannon (Jenny Livsey) and Dan (Daniel Evans) go on a boat trip and dive overboard into a Narnia-like Otherworld of Celtic legend.

At this point, heartsinkingly, the movie changes to Saturday-morning-type animation and we leave behind the real-life drama of Lleu's discovery that he is adopted: far more dramatic and interesting, frankly, than anything in the fey, prog-rock world where he spends most of the movie.