If anything of Team Viking is true, James Rowland is a dangerous man. In order to make good on a promise made to his closest friend, he decides to give him a proper Viking burial, complete with burning boat (and inevitable criminal charges). It is a testament to Rowland's warmth, wit and humour that Team Viking becomes an eloquent paean to friendship and not the litany of a psychopath on a rampage.

Rowland uses humour to ease into the story – getting close to the edge with his observations on his grandfather's attempt to tackle Christmas dinner under the influence of senility – but finding a way to lighten the dark humour by acknowledging how inappropriate it might be. Once the story takes a deeper turn – a friend dying of a rare and terminal cancer – he manages the transition through juxtapositions of fun and anguish, and a rough, jagged, episodic structure.

Rowland's doubts about his behaviour – and the question of how much of the adventure is true – transcend any traces of arrogance or self-satisfaction: the constantly shifting energy enthuses even mundane moments with the kind of childish grandeur that possibly inspired the viking funeral in the first place. It's a virtuoso display of post-modern storytelling.

Summerhall, 9, 13, 16, 20, 23 Aug, 9pm £12.50 (£10); also as part of Songs of Friendship, 11, 18, 25 Aug, 9pm, £25 (£20).