As you might guess from the title, Young Caesar will trace Gaius Julius Caesar's youth and friendship with Marcus Junius Brutus. Iggulden's series traces their early career as Roman soldiers, follows them through romantic love and brutal warfare before placing them on the Senate floor. The books end long before Et tu, Brute?, so don't expect friend to stab friend, just plenty of allusions. I imagine it will be as corny as that sentence implies. After all, Caesar was old enough to be Brutus' father (and ancient rumors claimed he was, since he had an affair with Brutus' mother), so the idea of them being boyhood friends who quarreled with wooden swords and rode ponies is extremely farfetched.
The life of Caesar is rich for a biopic, and he's never gotten a full treatment beyond adapting Shakespeare's play (he's usually just a love interest in a Cleopatra movie), so it's a shame Hollywood will pick the silliest angle to go with. Especially as I think Steers is an interesting pick. He's familiar with the traumas and tribulations of teenage life, and his boyish protagonists are usually in situations as alien as Caesar's life is today, so he could probably make it relatable. It's just a shame they want to go the silly route with it.