Batman has taken cassie off active field duty while he re trains her on defensive techniques. The training does not go well so she ends up sidelined for weeks. He even gives her a cd rom which gives her a run down of every known martial art. she still cant beat batman. so she decides to go out anyway. she is successful and oracle finds out but tries to dissuade her from her vigilantism.
Cassie goes anyway even after batman says the reason she is being retrained is because he does not want another Jason Todd situation on his hands. Cassie goes out one night and finds lady shiva. Despite knowing she cant beat her she tracks her down and intercepts her assassination attempt on a woman. she is defeated in one punch.