。
She accomplished the plan.
Literal
She [topic-は] that plan [object-を] accomplished.
成し遂げる is a compound verb pairing 成す ('to bring about / achieve') with 遂げる ('to carry through to the end'). The compounding intensifies the sense of completion — not just 'finished' but 'saw it all the way through, against the odds'. Compare bare 終える ('finish') or 完成する ('complete'), both of which describe completion neutrally; 成し遂げる carries the connotation of effort, perseverance, hard-won success. It's the verb of biographies and obituaries, the kind of 'accomplish' you'd find in 偉業を成し遂げる ('achieved a great feat').