The Legend of Larnshan's Wyrm (OSR)

From the introduction: A heroic knight spent a night of passion with a beautiful water fey. Unbeknownst to the knight, she was a transformed beast and fell pregnant to him. She fed on the children of town folk to nourish her unborn. The knight slew her in her beast form and as he realized his error, he returned her to the water... from her corpse sprang forth terrible forms. The Knight is long dead, and the foul wyrms have reached maturity. The creatures now raid the newly settled homesteads and the PCs have been asked to slay them. User summary: For 5th - 6th level characters.