"Midnight shift" refers to a work schedule where people work during the late hours of the night, usually starting at or around midnight. Full definition
I didn't have easy access to a bathroom, and had diarrhea every night, plus I worked midnight shift. (mommypotamus.com)
Montanino, who commands the «first platoon» or midnight shift for the department, said he was not certain if he would be recalled to appear. (timesunion.com)
We'd let them bake / cook for six or seven hours, depending on how the shift was going (midnight shift always, always brings in the after - dark disasters, and can be a wild goat rodeo!) (melaniecooks.com)