The ride is an upgraded installation and direct replacement of the former Lost River of the Ozarks attraction, which was removed following the 2018 season, as well as an investment to celebrate the park's 60th anniversary.

In January 2019, a representative from Silver Dollar City confirmed to media sources that the popular Lost River of the Ozarks raft ride, which opened in 1985, had been retired and fenced off to allow for the construction of a new project for 2020.

[1] On April 3, 2019, Silver Dollar City, LLC filed three trademarks that were quickly deduced to be in direct correlation with the project; Lost Caverns, Pearl's Float Trip, and Mystic River Falls.

[3] In June/July 2019, park socials began to post cryptic teasers referring to their new project, drawing ties to the local Marvel Cave landmark and using the hashtag #LostCaverns, eventually confirming August 13, 2019 as the set announcement date.

[4][5] As promised, on August 13, 2019, Mystic River Falls was formally announced alongside the brand new Rivertown area and amenities, and would celebrate the park's 60th anniversary that year.

In June 2020, shortly after major construction had commenced on the attraction, Mystic River Falls would begin testing and sending rafts around the course.

[citation needed] Once dispatched, riders make a left turn into the primary conveyor belt lift, before being launched into the “river” portion of the ride.

This concludes just after a tunnel, in which signs warn the riders of an upcoming mine shaft, and a second conveyor belt leads to the loading zone for the ride's signature-elevator lift and elevated section.

As the elevator rises, the tower structure spins a full 180° and dispatches the raft into a high-speed 270° helix, offering riders panoramic views of the Ozarks.

[citation needed] In the present day (dubbed to be in the 1880s), Pearl and her husband Leo run the Mystic River Expeditions touring company and challenge anybody willing to explore and find the hidden passageway.