Sasha and Tom Cruise. Volume 1. With the Vikings

Sasha Bazarek loves physics and experiments very much. He is the best student in the class, and he even has a fan club. He is secretly in love with Zhanna but is too afraid to even say hello to her.
More than anything in the world, Sasha wanted to receive a rat as a birthday gift, but his mom gave him a Chihuahua - a dog that, to the boy's complete disappointment, doesn't know a single command. In retaliation, he named the puppy Tom Cruise, after his mom's idol. One morning, Sasha found the dog in his father's study. Tom Cruise was all smeared with a strange glowing ointment. From that moment on, strange things started happening to them: like wizards, they overcame space and time and ended up in the most unexpected places...