This is just a list of known but unresolved plot hooks and things to investigate, with a link to the session in which they first appeared, if one is appropriate.

Mysterious Things in General

• The Singing Stone 
• Haunted House in Saltmarsh  (I'm not actually sure we were told this in character, but I'm going to assume we were!)

Mysterious Things in the Dragon's Delve

• Divining Pool of the Moon Goddess Glorius

• That #@$%ing Beholder Ocular Tyrant
• Pedastal Room
• Heartbeat Room
• Voice in the Tree Chamber