Heavy Lines, the debut EP from the quartet of UNC grads known as Happy Abandon, begins sparse and slow, with just a twinkle of keyboards and guitars. But “Severed Seams” builds dramatically toward a lush surge, its ebb and flow not unlike the patterns of a banjo-less Mumford and Sons. Sighing, melancholic verses explode into a rousing instrumental coda that pushes into post-rock. It’s a fitting introduction to Happy Abandon’s entire approach, which attempts to shape glimmering tunes from familiar sources. The quartet has more audacityand, in most places, better executionthan might be expected from a band that’s only one year old.

Having Grammy-nominated producer John Custer, best known for his work with Corrosion of Conformity and Cry of Love, working the boards certainly helped Happy Abandon with this polished pop-rock. Custer, for instance, envelopes Peter Vance’s gauzy vocals in reverb, while layer upon layer of bright guitar and coruscant keys add texture around it. Occasional orchestral additions conjure a sweeping sense of melodrama, indicative of the members’ theater backgrounds.

Vance’s lyricism is often rich in imagery and alliteration, whether the meaning is as obscured as his vocals or when his confessionals are direct and emphatic, as on the title track’s tale of an abandoned lover. Despite the narrator’s sense of regret, “Heavy Lines” soars with a crescendo of chiming guitar and stormy percussion. Pared back to acoustic guitar and atmospheric embellishments, “Window” follows with solemnity.

By the EP’s end, or on closers “Clutter” and “Love, Like Language,” Happy Abandon actually seems capable of forging its own identity. The former’s busy arrangement lives up to its title, shedding the measured austerity of its predecessors. The incredibly memorable “Love, Like Language” pits a propulsive bass line and fat, fuzzy synth against dreamy vocals.

Actually, the strength of “Love, Like Language” shows the weakness of its companion tracks; though melodic, many of them lack the hooks to stick as well as the kicker. But as a dynamic first statement, Heavy Lines makes a case that Happy Abandon could break through to the big stages its idols occupy, however slowly the start.