The Bastion of the Boglings, or, The Forgotten Sanctuary of Solis

From the introduction:

Hook: Children have been kidnapped from a local village! The tracks of bipedal frog-like beings lead to a ring of ruined standing stones. There a crumbling staircase descends into the dark...

Wherein: The party confronts a small tribe of frog-like boglings and finds all the children eaten but one. They may also learn that this complex once served as a religious site to the now-defunct faith of Solis, God of Light.