Vengeance fr one’s wrongful deeds. Moral or legal retribution for one’s error or wrong doing. Karma. ‘Hammer’ suggests a great moral weight has come down on someone for their sins. (Compare to Chickens comes home to roost; Karma; Hammer falls; What goes around,comes around or Pay back.)

“When the boss returns, the hammer will fall on the vice president for her bad decisions during his absence.”