A skeptical historian discovers a portal to different time periods in a cave, and after accidentally traveling through it, must navigate the dangers of different eras to find their way back home, only to realize they have been time-traveling their whole life without realizing it.
A historian who is skeptical of the existence of time travel but is drawn into the mystery when they witness the portal in action.
The historian's skepticism is challenged when they accidentally travel through the portal and must navigate the dangers and challenges of different time periods in order to find their way back home.
After a series of harrowing adventures in different time periods, the historian finally finds their way back home, forever changed by their experience and now a firm believer in the existence of time travel.
Twist: Upon returning home, the historian realizes that they have actually been traveling through time their whole life without realizing it, and that the portal was just a physical manifestation of their own ability to time-travel.