EMA, Cargo, London

Captivated by an American screamer

Howling success: EMA on stage at Cargo BURAK CINGI

The latest in what seems like a never-ending supply of precocious female talent emanating from the States, EMA is fresh off the boat and getting ready to conquer Britain. Harder than most to pigeonhole, she slips serenely through a surprising variety of musical styles across a short set, with only a hard spine of Americana and her signature howl to knit her songs together.

"The Grey Ship" is a slumbering seven-minute masterpiece of ululating Southern gothic, moving through all the gears at once from breathy to pounding with one glorious bass drop. This is the pattern of all her best songs, which wend seamlessly from intimate sotto voce and string-picking to massively wrought choruses in a matter of instants. "Milkman" sounds as big as anything by The Arcade Fire, and she's doing it with only half the personnel.

It's all heart-on-sleeve, an ambitious sound far too big to be contained by Cargo's tiny back room. They can try to be too lofty, a small band forced to rely on a backing track to achieve the sound they want. At times, too, they indulge their muso fantasies too much, trying to build their songs out of all sorts of ugly discordance. Still, they're tight as hell and an impressive musical unit – they just need to learn that less really can sometimes be more.

EMA herself is never less than captivating with her pitch-perfect banshee shriek and attendant strut. She prowls the small stage in that fine tradition of riot grrrls past, though in some ways she's a little studied: her shirt has "Emptiness" scrawled on it in a jaunty font, her bleach-blonde hairdo tumbles into her eyes suspiciously well, and her on-stage patter is very Courtney Love, but she's got the talent to make it all impossible to begrudge.

The show – only nine songs – moves through lots of moods, reflecting both the dreaminess she shows on record and a snarlier tribal-grunge feel. By the time we reach "Red Star", it's just a thick fog of rumbling bass, vicious guitar squalls and bashed drums. Magnificent, in case you wondered, and absolutely compelling.

We close on "California", which is the closest thing EMA will get to a hit. It's a slow-burn spoken-word piece, grey-washed with layers of My Bloody Valentine-esque distortion, which sees her flip a venomous bird at everything the so-called Golden State seems to stand for.