one's last hope; one's only hope; the last hope
A set phrase meaning the final thing or person one can rely on in a desperate situation. Often used with 頼る, すがる, or similar verbs.
He relied on his last savings as his only hope.
That doctor was her last hope.
The expression literally means 'rope of hope,' evoking the image of a lifeline or the last thing to cling to. The exact origin is uncertain, but it is a conventional Japanese idiom.