Using live animation, puppetry and song, The Adventures of Alvin Sputnik tells a fantastical tale of heartbreak and heroism in a world beset by climate catastrophe. Humanity's mistreatment of the planet has taken its toll: sea levels have risen with devastating effects and only a few souls remain, their ramshackle houses teetering precariously on the tops of the tallest skyscrapers. Something must be done if the human race is to survive. Alvin Sputnik steps up.

Performed with considerable skill and charm by Tim Watts, this one-person show takes a sweet and imaginative approach to some dark subjects. Alongside Alvin's mission to save the earth – a mission that involves searching the bottom of the ocean for the volcano that leads to world at the centre of the earth, no less – runs a personal journey, that of reconciling himself to the recent death of his beloved wife.

The show is a touch languorous in its pacing: the live songs Watts performs on the ukulele in particular do not take the story anywhere, even if they are sweetly melancholic. It's also overly sentimental at times, relying too heavily on the audience being charmed by Watts's admittedly adorable creations. But despite these faults, The Adventures of Alvin Sputnik has real heart and is likely to bring as much delight to Edinburgh audiences as it has done elsewhere on the international festival circuit.