The Legacy states only a male will rule. Given that fact, Eileen doesn't feel too inclined to take life--and Alpha duties--seriously. Hunters are at large, her family's keeping secrets, and the bordering territory's Alpha is back. His arrival causes everything to spiral downward; Eileen resents him and refuses to make her Alpha training on him any easier.
After all, what's The Legacy got to do with her, a girl who will never rule?
Nothing. So: bring on the rebellion.