It's not that ghosts don't show up during the day. Danny knows just how (not) effective sunlight is for getting rid of ghosts. Still, the part of him that's still human expects nighttime to be worse, and his enemies are happy to oblige.

Every night, Danny goes out to fight ghosts. Most nights, he gets knocked around a bit. Some nights, he gets beaten to a pulp (literally – yay for healing fast).

Every night, he's in danger.

And just about every night, his friends follow him right into the thick of it.

He's too scared to make them leave.