Semashko was a member of the third squad lead by Sergeant Antonov in the Red Army. He is first seen in the first Russian Campaign level where you get off of the train on a temporary railhead built near Botonov on July 4, 1943. He boards a truck with the rest of the squad going to an ammunition bunker, one of the other trucks was destroyed by artillery and the soldiers in that truck were killed in the explosion. He survives and heads to the bunker to get ammunition. He holds off a German attack on the line and helps retake the left flank. He assists Yuri in taking out the Elefant Tank Destroyer with TNT. Then he goes with his squad to take a village and hold it while the reinforcements make their way to it.
Later, on July 11, he assists them in taking Ponyri. In this level he also takes out two tanks while Yuri covers him, he is in the force outside of the factory distracting the Germans with Antonov while Yuri is taking it with other soldiers.
He and the rest of his squad is transferred to the 15th Guards Rifle Division and takes part in the assault on Kharkov, he helps take the square and the train station. He survives the battle, and is relieved when the troop train with fresh recruits storms in. It is unknown what happens to him after the end of the game.