let in for

let (someone or oneself) in for

To involve someone or oneself in something, especially that which proves to be more intimidating, demanding, or overwhelming than one was expecting. I hope you know what you're letting yourself in for with this case—it's going to drag your reputation through the mud for a while. Just what have you let me in for, Tom? I said I wanted to earn a little bit more money, not get involved with the Mafia!
See also: let
Farlex Dictionary of Idioms.

let someone in for something

to cause someone to be involved in something, usually something unpleasant. Fred had no idea what his brother had let him in for when he agreed to take his place in the race. Jack didn't know what he was letting himself in for when he married that dreadful woman.
See also: let
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • leave (someone, something, or oneself) (wide) open for (something)
  • leave oneself wide open for
  • leave open
  • leave yourself wide open to something
  • leave (someone, something, or oneself) (wide) open to (something)
  • reproach (someone or something) with (something)
  • reproach with
  • keep in sight
  • keep sight of (someone or something)
  • keep sight of somebody/something