Take an ordinary, unhappy 14 year old, Phoenix. He's bored by school, hates his step-father, has no control over his life. The only things he likes are computer games and martial arts.
Add in smart, miserable Jade. The youngest of seven girls; a misfit; her own mother doesn't get her. All she likes is books and botany.
Throw them into a computer game - 80AD - AND into their avatar's bodies. Phoenix and Jade aren't kids any longer. They're 17 year old warriors, confused and trapped in an ancient world of warfare, magic and death. They're stuck in 80AD Britain. To Phoenix, it's fun - a gamer's dream come true. To Jade, it's a nightmare.
In order to get home, they have to play out Level One, defeat the Romans and find the Jewel of Asgard. Fail and they'll be stuck in the game forever.