O No! (Assembly Roxy, Edinburgh)

"I've got a lot of layers on," warns Chris, as he and Jamie Wood perform Yoko Ono's "Bag Piece": 'Two people get into a bag. They undress.' It's a lovely moment: the banality of everyday life slammed into the dreamy utopian whimsy that Ono and John Lennon were privileged enough to practice. Accountants don't have time to strip off in bags. Nurses can't repeat a word until dawn.

"Canoe," intones Wood on a grainy tape, as per instructions in Ono's book Grapefuit. "Canoe… Canoe… Canoe." His long-suffering partner (and director) Wendy Hubbard stirs in the bed, sleepily wondering why, at 4am, he's repeating the word canoe, and whether he might consider doing so in the next room.

O No! is an homage to Yoko Ono, and the nappy-clad Wood, with his straggly Jesus hair and his kind, kind eyes, really tries to revive the spirit of her work – the love (love, love) that she and John Lennon preached and practiced. "No cynicism," he demands of himself. "No cheap laughs."

Consider this an act of cultural restoration: stripping away all the accumulated baggage and iconography to find the truth of Ono's art. If she seems ludicrous today, a pastiche of a pastiche, Wood is able to detach the art from the artist. When he performs "Cut Piece", inviting us to snip bits of his black dress off with scissors, it comes as a surprise: genuinely violent and genuinely vulnerable. This is the live art equivalent of cleaning up an old oil painting.

'This isn't wacky for wacky's sake'

Not that it's po-faced – far from it. Wood's careful to walk that tightrope, and Ono's art is sometimes outright dumbass. Blood Piece, for example: write a letter in blood, keep going until death. ("No Jamie. Jamie, no," scolds Wendy.) Such is the way of the avant-garde, and Wood reminds us of the term's origins: the first erratic line of attack intended to confuse and disorientate the enemy. This isn't wacky for wacky's sake. It's oppositional and fierce and idealistic.

The onus, though, is on us, the audience, to give these pieces a chance. Any trace of cynicism or snark and Ono's art shrivels, but Wood cuts through to forge an accepting, even a loving, spirit in the room, coaxing us, gently, into playing along. We pass the sun around, hold hands and touch each other in the dark. We become an oddball orchestra, creating a beautiful noisy mess as we please. It's a blissful hour, giddy and gladful.

But there's rigour beneath – in his parents' discussion of their own mundane, but nonetheless steely, marriage, and in the gunshots that crack through the piece, slamming Wood/Lennon to the floor. A reminder that love can be deemed dangerous. It's a powerful thing, and Ono, far from being an impish kook, was its greatest exponent.

O No! runs at Assembly Roxy until 31 August