Then where is the Lannister army? At Casterly Rock? Why arent they in kings landing?
Can't remember the exact place but they were occupied. They also didn't have a proper, loyal, brave commander like Tarly. You can see how disorganized they were by what Jamie observed when he went there.
The problem is the HUGE inconsistency seen in the TV series. Stannis verbally states that Lord Tarly was never defeated in battle (TV series) and the same fact is mentioned in the book. So what the #%&* is he doing while their "girl and boy" are being held captive by the faith (TV series does not explain how so many men who could wield a weapon went and join the faith. The book does in detail.) without clear evidence? Where is this invincible general?
To make matters worse:- in the TV series, Ser Loras is the heir to Highgarden!
(Not true in the books. Ser Loras is basically the embodiment of heroic virtues. See how intelligent he was by the way he discussed the facts regarding Renly's death with Jamie. No interest in women or wealth. It was his dream to become a kingsguard and his house has no problem with it. His character is gang raped in the tv series).