With the guidance of Mau (a.k.a. Phage), Ashwin Pember, recently ascended Ancestor of the Sunspot, projects their mind to Earth via the Tunnel Apparatus. Only, they do this to become the new headmate of the twenty-seven year old autistic transgender plural system of Sarah and Goreth Ampersand of Portland, OR, who think that Phage is their old imaginary friend. Unfortunately, Sarah and Goreth already struggle to manage their already difficult life. They’ve been leaning on their housemates and friends for support, but playing host to an alien being challenges them all. Furthermore, there's an important reason Phage came to Earth in the first place, and it needs Sarah and Goreth to cooperate with Ashwin in order to achieve its goals. The Tunnel Apparati Diaries tell the story of how the Sunspot Chronicles came to be translated and published on Earth, but what does this mean for humanity? Because there’s a probe full of construction nanites left somewhere in the mountains of Washington State and someone needs to take responsibility for it before it falls into the wrong hands.