to the mercy of
or to the (tender) mercies of
: without any protection from (someone or something you cannot control)对…无能为力；任由…摆布 -
He had to leave his boat to the mercy of the storm.他只能让自己的船听任暴风雨摆布了。
-
As the army retreated, the people were left to the mercies of the advancing enemy.由于军队撤退了，老百姓对进攻的敌人无力抵抗。