plumb the depths

to reach the lowest point
اصطلاح/ به انتها یا آخر خط رسیدن
Roy plumbed the depths of despair when his wife left him
They must be really plumbing the depths ( = must have been unable to find anyone better ) if they're offering the job to her

منابع

• https://dictionary.cambridge.org/dictionary/english/plumb-the-depths