After reviewing Ryndyll's notes, Bolwing will accompany the Arch-Mage to Archen Grangrove to attain the tome Frenshade.
The book will cost the Arch-Mage $10,000.
Bolwing will explain that he thinks Ryndyll might be trying to destroy Nirn and ask the Arch-Mage to join the Dominion at Glenview to learn more about him.
Depending on how the quest Dog is completed determines when more dialogue will open up with Bolwing and the main quest can be continued.