Attention action-film fans! There’s a fantastic new one out in theaters, just released by Lionsgate, which is a mayhem-filled fever dream from Finland, written and directed by Jalmari Helander, called Sisu. That’s a Finnish word defined at the beginning of the film, with no exact translation into English, but meaning something like “a white-knuckled form of courage and unimaginable determination” which “manifests itself when all hope is lost.”

It’s about a tough old Finnish commando named Aatami Korpi (the magnificently bearded Jorma Tommila) who fought in the 1939–1940 Winter War against the Soviets and became legendary as a one-man anti-Russian hit squad, so unkillable they referred to him as Koschel, “The Immortal.” The character is partly inspired by Simo Häyhä, aka the White Death, a Finnish military sniper reputed to have killed over five hundred enemy soldiers during that conflict. Korpi is also partly inspired by the John Rambo character in the best Rambo movie, First Blood.

Old man Korpi, we’re told, disappeared into the wild wastes of Lapland to get away from World War II, and we discover him living out there alone prospecting for gold when the retreating Nazis, in their scorched-earth spree of destruction through northern Finland near the end of the war, finally reach his desolate outpost.