Doomsday weapon in the ocean of the past

RFS "Belgorod" is a Russian nuclear submarine with underwater stations and unmanned nuclear vehicles "Poseidon", which he was just testing in the Pacific Ocean, but when suddenly something appeared on the radar, Captain Alekhin said to send the "Harpsichord" for reconnaissance, when the "Harpsichord" discovered something, something that looked like a cube, the cube glowed and emitted a lot of energy, when it was transferred to the submarine, it disappeared and the submarine too.... "What should we tell the authorities," said sailor, - I don't know the cabin boy, I don't know, but now the main thing for us is to get out of here.