Geology expert Professor Mike Rackman is studying the Alpine Fault, a 600 km long crack that runs the length of New Zealand's South Island. Every 300 years or so, the fault cracks causing massive earthquakes and tsunami. Mike hopes his studies will help predict the next big one. Unfortunately, he disappears after an accident involving a local hunter. Jack Stewart and his cat, Chainsaw, have had earlier adventures with the professor where they travelled back in time. Jack thinks the professor has done it again, and is trapped somewhere in the past. He and Chainsaw set out to save him. They end up in the year 1409, just hours before the fault is about to crack. Not only must Jack save the injured professor, he must also convince the local whanau of the coming disaster. The problem is, if he succeeds then the only way back to the 21st century will be closed for another 300 years. Eagle Swamp is the second story to feature Jack Stewart, Professor Rackman and Chainsaw. The first was Crown Park. Each adventure can be read independent of the other.