The pair first rescued their team from a precarious 52 for six to total a respectable 256 all out, with Crook hitting 92 from 104 balls and Bracwell 81 from 134 deliveries.
Bracewell then made an instant impact with the ball as the Bears slumped to 25 for two in reply, before Crook struck a late blow to dismiss Sam Hain as the home side ended the day on 100 for four, still 156 behind.
It was a remarkable turnaround, but head coach David Ripley will be more concerned with his side’s continued batting woes, with once again the top order, which didn’t include Rob Newton, failing to fire.
Northants won the toss and decided to bat, only to see Ben Duckett (4), Alex Wakely (3) Richard Levi (0), Luke Procter (19), Adam Rossington (4) and Rob Keogh (1) all falling cheaply.
Only Josh Cobb, with 29, showed any sort of resistance until the counter-attack from Crook, who hit 15 boundaries, and Bracwell, who hit 11 fours and one six, saved face.
That effort with the bat, and then the pair picking up three wickets with the other coming from Brett Hutton, means the County are still in the game, although former England man Ian Bell is well set for the hosts overnight as he is 55 not out.
Play resumes at Edgbaston on Saturday at 11am.