The story has an unusual time scheme
1. The story doesn't follow a chronological structure. It's mainly set in Scrooge's present, but it includes three separate episodes that have visions set in different time periods - Scrooge's past, present and future
2. Each individual episode with the ghosts doesn't follow a regular time scheme - each one contains several jumps in time
3. The linking sections between each ghostly visit are set in Scrooge's present, but they also don't follow the normal rules of time. Scrooge falls asleep after 2am, but he's visited by the first ghost at 1am that same night. The tolling of the "melancholy" bell shows that hours are passing, but the three visits only take one night