Liam O’Rafferty’s Paper Hearts Musical  at the Underbelly is certainly eager to win our hearts, and the feeling in the room is that this audience is very willing to lose them. To this mutually satisfying end, the cast of ten performers sing and act with gusto and talent as they tell the tale of the little bookstore and its battle against the inevitability of the online giants, as personified through the soured relations between store manager-turned-novelist Atticus Smith (Adam Small), and his CEO father, Robert. This latter, played efficiently by David Mullen, is impervious to his son’s distress, and is buying out the store and putting it online. Meanwhile, he’s also judging a writing competition, which Atticus is entering to save the shop. Robert is scornful: If ever a name was a lot to live up to, it’s Atticus.

Against this strained backdrop, Atticus is looking for love. When it walks into his life in the effervescent form of Gabriella Margulies as Lilly, one of Robert’s employees, a solid and likeable comedic partnership is formed, straight out of the romantic comedy tradition. They fight, they kiss (almost), they fight again. And it’s fun. Small and Margulies, as with the rest of the cast, are talented performers, and they easily win our hearts.

There is, however, a secondary element to the story – quite literally a separate plot, as typed – and acted out – before our eyes. As a refuge from his romantic and financial woes, Atticus throws himself (and us) into his novel. A romance/thriller set in WW2 Russia, these interludes reveal some delightful song and dance routines, choreographed by Lindsay McAllister – all stomping and clapping, and general knees-upping – as well as more excellent performances, in particular by Sinead Wall as Yanna, the novel’s protagonist. With a deep yet mellifluous singing voice and a wonderful way with acerbic one-liners, Wall also gives a delightful comic turn as Atticus’s insensitive ex.

Slightly distracting from all this action is the space itself. The diminutive stage is frequently cluttered by people and props, which gives a perpetual sense of chaos, but it is an organised chaos. Tania Azevedo’s direction is nothing short of spectacular, averting near-certain onstage collisions and turning scene-changes into choreographed art.

So far so good. Unfortunately, though a highly polished and thoroughly enjoyable production, with pleasant numbers and impressive musicians (most of the instruments are played by cast members live on stage), Paper Hearts doesn’t quite gel as a musical. The problem is the book. While strong enough to entertain, it won’t hold its own with the greats. The stakes are not quite high enough, and the resolutions a bit too easy in any case. Don’t let that stop you booking, though. It is a show of warmth and wit, well-deserving of support and, indeed, applause.