Meet Stefan, your typical teenage boy who likes to impress the ladies. Like most rich kids who has a dangerous dad, you will see him with his body guard/butler named Krieg. Stefan doesn't know about his father's criminal inclination with Gogol (Russian Criminal Organization headed by Ari Tasarov).
However, things will finally be revealed when a failed assassination attempt on his life surfaces into the picture. He learns that Krieg is actually a trained mercenary hired by his father for his protection. When Stefan gets abducted, Krieg holds Amanda and Nikita for interrogation.
Source: Spoilers Guide -- Nikita