creek

be up the creek (without a paddle) (informal, very informal!)

to be in a very difficult situation that you are not able to improve. If the car breaks down we're really up the creek. He'll be up shit creek unless he finds the money to pay off his loan.

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up the creek (without a paddle)

in an extremely difficult situation. All those people who have money invested in it are going to be up the creek.

Etymology: based on the idea of being in a small boat in a stream and not having a paddle (= short pole with a wide, flat part) with which to move it