George Vere: writer, director, producer, actor. This self-proclaimed genius is convinced that his tacky Star Trek rip-off is a work of staggering brilliance, but the rest of his cast aren't so sure. Pitched somewhere between Galaxy Quest and The Play That Goes Wrong, The Starship Osiris would be a perfect companion piece to Kill the Beast's Don't Wake the Damp from last year's Fringe.

It starts as a sci-fi pastiche – complete with crappy special effects, rubbish robots and cheesy songs – before descending into mutiny as Evans (Adam Willis) breaks character and leads the revolt against their pompous leader. The first half is funny but the second half really shines, personal grievances bubbling to the fore as the cast bicker and brawl.

The ingenious script cleverly blurs the line between fact and farce with Vere and Willis excellent in their dual roles but Lola Claire, Molly Bird and Jo McGarry also deserve praise for their high-energy performances, alongside Ian Fleming who provides live music and the odd deadpan one-liner. It's also worth noting that there'll be a special one-off performance on the last day of the run of Vere's 'masterpiece' in all its glory as 'originally intended' by the great man himself.

Underbelly Cowgate, until 27 Aug (not 14), 5.20pm, £10.50–£11.50 (£9.50–£10.50).