Professor Mike Rackman disappears while studying New Zealand's Alpine Fault. His young friend Jack Stewart believes the man is injured and lost in the 15th Century. Jack and his cat follow him back in time arriving hours before the fault breaks. Now all three are trapped in the past and only Jack can save them.
Eagle Swamp follows on from Crown Park, which featured the Taupō eruption. While Eagle Swamp mentions the earlier adventure it can be read independently.