Rascla wanted to conquer the universe and chose the Mitrans as his first target. He experimented with acidic warfare but found no way to pass the Mitran defences. Rascla caused a malfunction on board the Doctor's TARDIS, forcing it to land on Axa, moon of Rascla's native Torm. From there, Rascla brought the Fourth Doctor, Sarah Jane Smith and Harry Sullivan to Torm and used a Nucleonic Body Separator to possess the Doctor's body. He planned to use the disguise to infiltrate a peace conference on Mitra B and release deadly germs, killing the Mitrans.