Here I copy the list of THE HEECHEE SAGA
THE HEECHEE SAGA Book One: Gateway Book Two: Beyond the Blue Event Horizon Book Three: Heechee Rendezvous Book Four: The Annals of the Heechee
-------------------------
Source: https://www.goodreads.com/book/show/373399.Beyond_the_Blue_Event_Horizon?from_search=true
---------------------------
I also found Frederik Pohl - Heechee 05 - Gateway Trip.pdf
有关键情节透露