The film stars Noomi Rapace as Caroline Edh, a speed skater who is conscripted to join a team of soldiers for a dangerous mission to skate across sea ice behind enemy lines.

Jakob Oftebro, Erik Enge [sv], Dar Salim, Ardalan Esmaili, Aliette Opheim, David Dencik, Susan Taslimi, and Stella Marcimain Klintberg appear in supporting roles.

Upon arriving at the base, she is taken for a briefing with Colonel Raad and she meets the other soldiers recruited for the special mission: Karimi, Malik, Granvik (a sniper) and Captain Forsberg.

The Colonel explains that the team must cross the ice-covered Stockholm Archipelago on skates and deliver some canisters to a research base, named Ödö, which he says could lead to victory in the war.

Edh points out that this appears to be a suicide mission, but she is given a reason to try to make it: the chance to be reunited with Vanja, who has been found in a refugee camp.

While resting on a ship they find frozen in the ice, Granvik opens the packages, which contain vials of liquid with a biohazard warning, suggesting they could be some sort of biological weapon.

Granvik shoots a lone machine gunner in a pillbox on a rocky hill overlooking the ice, before the trio comes across the latter's comrades, frozen to death.

Edh, after insisting Nylund find seats on the fleeing helicopters, is found by Nordh, and reveals that she has secured the vials to an unpinned grenade.

The critics' consensus reads: "Black Crab can be exciting in the moment, but its bleak and derivative story add up to a fairly forgettable viewing experience.

"[2] Charles Bramesco, for The Guardian, wrote that "in narrowing focus to the plight of speed skater Caroline Edh (Noomi Rapace), director Adam Berg and his co-writers (Jerker Virdborg, author of the source novel, and Pelle Rådström) give themselves enough room to wriggle out of the most difficult questions their premise poses.

[...] A pacifist parable taking a brave stand against nothing, totally removed from the sociocultural landscape of today’s Sweden, it sounds out like one of Caroline’s screams into the howling Scandinavian wind – impassioned, futile, heard by no one".

[...] Black Crab has all the ingredients to grab you and take you on a thrill ride – and at times it achieves this – but it suffers partial collapse by the end because of its need to land a little loftier than necessary.

Noomi Rapace is powerful throughout, as a desperate soldier skating for her family, and the camera work out on the desolate, ominous expanses of ice is often gorgeous, but the film never lets us in on what's actually going on in the world and that lessens the impact of the final act".