when the chips are down

when the chips are down (when things really get difficult) — в трудный момент; в решающий час; когда приходит решающий час; когда прижмет, когда припрет; когда жареный петух клюнет

Example 1: When the chips are down, you can always depend on me to help out.

Example 2: I know my parents would come and help when the chips were down.

see also
[at a pinch]
[push comes to shovel]