Broadly speaking, Kingston upon Thames-based trio Arcane Roots are a post-hardcore band. They scoff in the face of such easy categorisation, though: 2010's mini-album Left Fire showed that the band weren't just going to fit into any conventional strain of music. While the post-hardcore scene in the UK in general has undergone a resurgence in recent years, Arcane Roots' ambitions are far greater than those of their contemporaries, certainly when it comes to their music. They have progressive tendencies that push them beyond the limits of genre; across 10 tracks, Blood & Chemistry explores post-hardcore, math-rock and post-rock, with a genuine pop song thrown in there for good measure. Their penchant for unpredictable song structures is set out immediately on opener 'Energy is Never Lost, Just Redirected', which starts off with delicate harmonies before an impressively heavy-sounding riff kicks the album off in earnest, drummer Daryl Atkins negotiating myriad time-signature changes and dynamic shifts with ease before a stunning chorus hits and reveals that underneath all the unpredictability, the band's sound is rooted in melodies that wouldn't sound out of place in stadia.

There are times when they hint at one day rising to conquer those larger venues; 'Belief' is an immensely powerful track that is perhaps the most immediate on the album, the band cleaving to a more conventional song structure for the track, and Andrew Groves delivering an excellent vocal performance. In a similar way, 'Held Like Kites' is a predominantly acoustic track that shrinks the trio's gargantuan sound down to something impressively intimate, the mid-tempo track adding another string to their bow. They can certainly do delicate when the mood takes them (see also: the acoustic coda to 'Sacred Shapes'), but the band usually focus on packing as many twists and turns into their songs as possible, which means their longer efforts, such as lead single 'Slow', are fascinating, keeping the listener on tenterhooks as they wait to see what will happen next. The band sometimes go off on tangents and let their more progressive side out, such as on 'Triptych', a song which features technical riffing and an elongated exploration of the band's heavier side, but they make sure to bring the song full circle and drop it back into the chorus when least expected.

There are a particular pair of songs on Blood & Chemistry which will bring the plaudits flooding in, and it's telling that they come from two different ends of the musical spectrum: 'Hell & High Water' displays a more textured side to the band, taking an already finely-layered sound to new levels of complexity, while epic closer 'You Keep Me Here' stretches to nine minutes and is essentially a song in two parts, the first containing arguably the finest example of melodic urgency on the record, and the second starting a slow build from an acoustic bridge into a euphoric finale that once again shows that the band can reach to the rafters if they so desire. The album stretches to almost an hour, but the constant changes of pace and dazzling inventiveness that drive it help it to fly by. Arcane Roots are an extremely talented band: this was hinted at by Left Fire three years ago, but it's now been confirmed by their debut album, which, instead of faltering under the weight of its own ambition, shows that the trio can fit in absolutely anywhere. Creative, melodic, and intensely passionate: Blood & Chemistry takes an unlikely mixture of elements and makes them work brilliantly.