The hottest night of the year and Blaine Harrison is wearing a boiler suit. You have to admire the commitment, if perhaps not the judgement.

Then again, this was a night that posed the question: when is a gig not a gig? Technically, Mystery Jets were at Mama Roux’s to play an outstore set ahead of the release of their new album, A Hole To See The Sky Through, next week. In reality, once they began, there was no qualification needed.

“Serotonin” provided a wonderfully bouncy beginning, drenched in harmonies before building towards something unexpectedly heavy. It was an early indication of the range Mystery Jets can cover without any of it sounding forced.

The first part of “A Hole To See The Sky Through” followed. Grandiose and weighty, it already felt like a significant piece of work, while the vocal interplay was top-notch throughout.

“Doomsday Waltz” began with a bassline and ended up concerning itself with the end of the world. Yet, as Mystery Jets have always understood, even the darkest ideas can be carried by melodies that make them seem strangely uplifting.

“Do you mind being our human guinea pigs?” Harrison enquired before “Long Lonely Road.” A new acoustic based song that the band haven’t played live very often on these shows, it ached with emotion but possessed plenty of conviction too. Given its message of hope, that balance felt entirely appropriate.

“Soul River” sounded enormous. Indeed, everything here was delivered as though it was tremendously important, but this one seemed to mean even more. Ollie Taylor’s guitar solo rang out around Mama Roux’s and gave the song another dimension.

Then it was time for a change of mood.

“Who wants a dance?” asked Harrison before “Bubblegum,” and this was certainly the one to do it to. There was a genuine groove running through it, loosening the atmosphere as the band moved towards some of their older material.

“Young Love” took an unexpected turn when a woman was pulled from the crowd to sing Laura Marling’s part. The song Harrison described as “a golden oldie” became something even more communal as a result.

As for “Two Doors Down,” I’m not in love with either of the women who live next door – or a couple of doors away, for that matter. If I were, though, this would be the anthem. There was a more relaxed, carefree feel to these older songs, and Mystery Jets appeared to be having enormous fun playing them.

“Someone Purer” finished things by building with tremendous skill, gradually working itself into something approaching a frenzy. Yet even here, as the music became more intense, its essential nature remained uplifting.

That is what the four piece do. They connect with their audience, too, making it clear afterwards that they wanted to sign anything people had brought and, just as importantly, hear their stories.

Mystery Jets, then: interesting, compelling and still capable of finding new ways to present themselves. You’d best believe this was a gig.

And a pretty good one.