The leaders of the Second Fondation are worried that another "power" is trying to push along the Hari Seldon plan, benefiting instead of destroying it. Yet, they are worried and want to know who and why they are doing it, and send out a mission to the closest lead, a planet named Gaia, to find out.
The whole Foundation Series is simply awesome. 7 books in total, they are all worth it. And all the rest of Asimov is worth it too. Especially the Robot Series.
Foundation Novels in Order:
- Foundation and Empire
- Second Foundation
- Foundation's Edge (this book)
- Foundation and Earth