。
She's gone.
Literal
She [topic-は] went-and-ended-up.
A spare two-character sentence resting entirely on the emotional weight of ~てしまう. The compact 行ってしまった captures both completion ('she went') and the regret/finality wired into ~てしまう ('and now she's gone'). Without the auxiliary, 行った would just say 'she went,' factually neutral. The auxiliary is what colors the action with feeling. In casual speech this contracts to 行っちゃった.