虎落平川 hǔluò-píngchuān
[a man who loses position and influence may be subjected to much indignity] 老虎从山里来到平地。比喻有势力者失去了依仗或人遇到了倒霉的时候
虎落平川被犬欺。——清· 钱彩《说岳全传》