step into the breach

US /stɛp ˈɪntu ðə briːtʃ/
UK /stɛp ˈɪntu ðə briːtʃ/
"step into the breach" picture
1.

prendre la relève, intervenir, combler le vide

to take action when another person or group is unable to, or to fill a gap in a difficult situation

:
When the lead actor fell ill, his understudy had to step into the breach.
Lorsque l'acteur principal est tombé malade, sa doublure a dû prendre la relève.
The volunteers had to step into the breach when the regular staff went on strike.
Les bénévoles ont dû intervenir lorsque le personnel régulier s'est mis en grève.