In last year's Fringe First-winning The Initiate, playwright Alexandra Wood showed audiences how great she is at creating tense, dark drama. The Human Ear is much grittier, more gruesome, and ultimately a little less satisfying.

Lucy is reunited with her brother Jason after 10 years, a few months after their mother dies in what we assume – though it's never articulated – is the 7/7 bombings. But her boyfriend is suspicious; is the man really Jason? He goes to Inverness and brings back a human ear that says otherwise.

Wood's quickfire dialogue is impressive, effortlessly creating a taut atmosphere (though the faint, menacing background music feels unnecessary). Paines Plough rep actors Sian Reese-Williams and Abdul Salis are great too, yet it's the lighting that's the real star here. Roundabout's innovative LED system comes into its own, and swift changes in lighting are used to effectively switch between time and location.

But the rhythm of The Human Ear feels a little too staccato, and it's hard to settle into what's going on with so much back and forth. It's an impressive production, but a little more breathing room might help it make a bigger impact.

Roundabout @ Summerhall, 560 1581, 17, 20, 22, 24, 26, 28, 30 Aug, 3.35pm, £15 (£10).