The Yestertime Shift: Yestertime Series, Book 4 (Unabridged‪)‬

Keith Miller, an urban explorer, leads small groups of thrill-seekers through abandoned buildings. The exploration of an old mountain inn goes horribly wrong when the group accidentally accesses a time portal that takes them to 1917, a distant and dangerous time.

Former time traveler Ray Burton learns of their disaster and tries to help from afar. However, something alarming has happened to the portals.

Has Ray unknowingly put the travelers’ lives in jeopardy?

As desperation sets in for the travelers, they begin to realize that they are facing an even greater peril than they thought…