Billy is sitting in the bath reading a book, together with his rubber duck, Lucky. Lucky the ducky has a story – which takes us back in time to when Billy was 17, and the Paperboy of Pebbleton. Having successfully completed a list of impossible tasks set by the "love of his life" Cecilia, Billy discovers she has added on just one more... following a recent accident at sea, a cargo of 7,000 rubber ducks have been unleashed, and she tasks Billy with finding them.

Setting out to educate children about some of the problems facing our seas, this show approaches serious topics with comedy, anthropomorphic characters and songs. We meet gulls caught in four-pack rings, crabs living on the Pacific garbage patch, and polar bears struggling to get along now their ice is melting. As Billy takes his bathtub boat through the seven seas – clocking up his duck-o-meter all the time – we are treated to song, dance, and fabulously groan-worthy maritime puns.

It is very difficult to make a children's show last an hour while keeping their attention, but One Duck Down achieves it. There were some younger children who fidgeted a bit, but for the most everyone was enthralled. It is a credit to the show that not only did the children giggle with delight, but the adults genuinely laughed out loud as well. The humour ranges from clowning to fart jokes, with a few over-the-children's-head double-entendres thrown in for good measure; it never feels tired, genuinely having something for all ages.

On the day I attended, some of the singing was too quiet relative to the music, making the words difficult to hear. That was a great shame, because the songs are very good, and when they were sung loud enough really lifted the performance and added interest for the children. Alice Bounce sang particularly well, with excellent enthusiasm. But I felt that more could be made of encouraging the children to join in with choruses (as they did in the North Pole song), which would add some energy and get them even more engaged.

Each scene combines serious environmental issues with absurd and funny animal stories, and of course a duck; the result is well-pitched to inform and raise awareness, without feeling like a lecture. Best of all, there is an uplifting, satisfyingly happy ending, showing that true love is about shared interests and passions more than about how people look. This well-thought-out and engaging show has all of its ducks in a row.