Mack runs things at the colony, while Ren is the engineer who keeps it all going. The colony is self-sufficient, using 3D-printers to craft whatever they need - food, clothing, utensils, medicine, anything - and everything runs quite smoothly as the entire colony follows the strict recycling policies so they never really need to make an impact on the planet on which they now live. Homes are biological in nature, filtering out impurities naturally and Ren was also the designer and builder for these. Aside from the mental frustration of knowing the real truth behind Planetfall, everything was going pretty well, that is, until a stranger showed up outside of the colony walls.
It all started many years before, when Ren's dearest friend Suh-Mi experienced a life-threatening event that left her changed. She became convinced that she was "the Pathfinder" and that humanity's salvation from a slowly dying Earth was to be found in a place she called God's City, located on an alien planet, and she convinced others to join her on that journey. Suh-Mi was right and the colony still stands, but at what cost?
Fast-forward 22 years and Ren lives a quiet and very private life, tinkering with the printers and spending her time fetching items from the Masher (the recycler) that she deems fixable. The yearly celebration is soon to occur, and as always, all of the colony members hope that Suh-Mi will emerge from God's City with a message from the creator. Oddly enough, a bedraggled and weary young man shows up at the colony's borders and he bears a striking resemblance to Suh-Mi.
The young man, Sung-Soo, causes quite a stir because it was thought that no other humans existed on this planet. During Planetfall, the other two pods crashed and there were no survivors, yet this young man tells a different story, one of difficult survival. He is Suh-Mi's grandson and the only remaining descendant of the survivors of the crash. Naturally, the colony bustles with fear and questions. Did they not search hard enough? Did they not do enough to find their fellow travelers? Only Mack and Ren know the truth of what really happened, and Ren is a reluctant conspirator at that.
Soon, Sung-Soo finds a way to crack Ren's tightly guarded surface, partly because of his strong resemblance to a woman she deeply loved and misses so dearly, but also due to his eagerness to learn and become a part of the community. Before his arrival, her only escape was to sneak into God's City, a dangerous adventure at best, and explore, finding strange and interesting things. When Ren opens up to Sung-Soo, things begin to rapidly change and her tentative hold on her sanity begins to unravel. Can she continue to keep the secret that she and Mack have harbored for over two decades, or will it reveal itself anyway?
Planetfall is a deeply moving and riveting book. It has little bits of everything, from sci-fi, to drama, to horror, to romance, to slice-of-life moments, and it is engaging from start to finish. Ren is a deeply conflicted and layered character and reading as her story unfolds bit by bit caused me to become really invested in her as a character. If you enjoy good sci-fi, check out Planetfall.