[hǔ luò píng yáng]   

虎    落    平    阳    平阳：地势平坦明亮的地方。老虎离开深山，落到平地里受困。比喻失势。

虎落平阳，平阳：地势平坦明亮的地方。老虎离开深山，落到平地里受困。比喻失势。语本清·钱彩《说岳全传》第四回：“虎落平川被犬欺。”

It was as though a tiger left his hills and descended to the plains

虎踞鲸吞    虎视耽耽    虎踞龙蟠    虎穴龙潭    虎窟龙潭