The Bainbridge Volunteer Fire Department responded to the scene at 11:42 p.m. after a passerby observed heavy smoke coming from the building.
Upon arrival, firefighters encountered heavy flames, Bainbridge Assistant Chief Mike Aynes told the Banner Graphic.
The department immediately called for mutual aid, with Clinton Township, Roachdale, Russellville and Floyd Township fire departments all responding to the scene.
The building was a total loss, with only charred remains of walls and contents by morning.
Firefighters remained on the scene until 5:16 a.m. Thursday.
The business has not reopened since closing for the season last fall. Work was underway to prepare the restaurant to open this Saturday, May 19, with Joanna Polly serving as manager.
David Zeiner has owned the building since 2004. He said Thursday it is uncertain if the eatery will be rebuilt.
"I hope so, but I don't know what I'm going to do right now," Zeiner said. "I'm kind of in shock."
The exact age of the building is uncertain, but Zeiner estimated it was built in the early 1980s.
No damage was done to the adjacent Country Folks Farmer's Market and Greenhouse.
The cause of the fire remains unknown at this time. The Putnam County Task Force and the Indiana State Fire Marshal's Office are investigating the incident.