It's Groundhog Day... again.
Where once this meant "a groundhog looking at his shadow determines how bad winter will be", like St. Swithin's Day with fur, now of course it means TIME LOOP.
These are one of the six staples but a distinctly un-game-friendly one. When you only have three or four hours for a session, how much time do you want to spend doing the same thing again?
Having the PCs aware of the loop is the simplest solution. Then only you as GM have to repeat things, recite dialogue, see how long it takes them to work it out. Chances are, not long. Then let them sort things out, attempt to organise the looped period to their best advantage and, of course, see what happens when they throw themselves off tall buildings.
If the PCs are reset as well, things get more complicated. I'd suggest only playing things out once in detail, giving them some clues that this isn't the first time they've done all this, and enough motivation to leave a warning.
An extreme example from the time travel sourcebook for LUG's Star Trek - the ship finds a wrecked ship... which is itself from six hours in the future.
Of course, one option would be to let the PCs make their own time loops. Precognition as retcon and advance warning. Save Game as a meta-narrative-y power. "Just enough time to correct one mistake..."