Founded in 2013 by Artemis Fitzalan Howard and Eliot Salt, Bristol-based Deadpan Theatre return to the Edinburgh Fringe Festival after a sell-out run of Pre-drinks/ Afterparty in 2016, an original two-part musical written by Salt and Jude Mack. Third Wheel is also written and headlined by the duo, and looks set for another successful stretch in Scotland.

It has been two years since they have spoken, and the once close Polly and Eve are in mourning for their best friend Dylan. He has lost his battle with cancer, but before he died he decided to record a series of posthumous video instructions for them. Polly and Eve find themselves on a bizarre road-trip around the UK – the journey that Dylan was never able the make. Nonetheless, he travels with them, his ashes settled upon the knees of whomever sits in the passenger seat, kept safe in a Wizard of Oz lunchbox. Set to a witty Sondheim-esque score delivered by the onstage band, The Party in the Sky, Third Wheel is a hilarious tale of grief and love, and the courage it takes to be able to deal with both.

The band wear white, and are contained by cotton clouds and pearly fairy lights. The set is minimal: two cushioned stools transform and travel with the cast who are playing against a large projector screen. As characters, Polly and Eve are immediately likeable, and have a genuine chemistry onstage. In contrast to the selection of roles played by priceless comedian Sophie McQuillan, they are well rounded and stable; nonchalant as Dylan ghosts through them before becoming their brassy narrator, taking his place with the microphone in the beyond.

Composed by Joseph Ruddleston and lyricised by Salt and Mack, Dylan speaks in song. Jokes ferment and breathe heat into the action as Eve and Polly slowly break down and rebuild again, which works well to enhance the comedy of the script. During musical numbers, the cast would engage in sequences of movement to support the verse, and it is easy to watch. However, in some instances, the exercise becomes over-complicated and would benefit from deceleration. This excitable speed also translated into the delivery of lines, and at times volume and annunciation were a problem.

Perhaps the play’s most important innovation is its depiction of same sex relationships. It’s honesty and naturalness is reminiscent of the 1952 novel Carol by Patricia Highsmith, and is a refreshing representation of homosexuality. Twists and turns (although slightly predictable) warmed the soul and tickled cheeks pink, which made for a sincerely enjoyable experience. Salt and Mack have done well to create such an inspiring and endearing narrative – their future looks very bright indeed.

Third Wheel is playing at the Gilded Balloon Dining Room until August 27. For more information and tickets, see www.tickets.edfringe.com/whats-on/deadpan-theatre-third-wheel