For total time:

15 front squats
30 hanging knee-raises
15 thrusters
Then, rest 1 minute before continuing with:
15 front squats
30 chin-over-bar pull-ups
15 thrusters
Then, rest 1 minute before continuing with:
15 front squats
30 chest-to-bar pull-ups
15 thrusters
65 lb. / 45 lb. for the front squats and thrusters

Time cap: 15 min.

Workout 21.4 begins immediately upon completing or reaching the time cap for 21.3.