Based on the 2000 K-141 Kursk submarine disaster, in which 118 Russian sailors died. ''Kursk'' sank during a Russian naval exercise in the Barents Sea after explosions within the submarine. Twenty-three sailors survived the crash and desperately waited for help to arrive while their oxygen ran out minute-by-minute. The Russian government refused help from foreign governments for five days before agreeing to aid from the British and Norwegian governments.