It's probably not a good sign when a temple that's not been seen for millennia resurfaces. It's even worse when monsters start coming out of it. But hey, there might be treasure in there! And, you know, you should probably do something about those monsters. Maybe find out why the temple's back and make sure it's not going to destroy the world or something. But really, it's about the possible treasure. Sunken Temple is a new multi-system RPG adventure that's up on Kickstarter now.
The set-up is pretty much as you get from the title. A temple has resurfaced after millennia. Your adventurers get to go in and explore it. Each wing of the temple is dedicated to a different Old One, with its own monsters and purpose for being. The creators took inspiration from the Lovecraft Mythos when designing the module. It's set for characters level 4-6, and is compatible with 5th Edition, Pathfinder, and WOIN.
The campaign's a bit more than 2/3 to their goal with still 26 days left to go.