be hell-bent on something/on doing something

be hell-bent on

To be very determined to do something, perhaps annoyingly so. She's hell-bent on coming here for Thanksgiving, so we better clean the guest room. I'm hell-bent on getting an A on this exam, so I've been studying all week.

See also: on

be ˌhell-ˈbent on something/on doing something

be absolutely determined to do something stupid, dangerous, etc: Have you seen how fast he drives that car? I’d say he was hell-bent on killing himself.

See also: on, something