Why Did Teenage Elias Disappear?

After briefly reuniting with his birth-mother Sarah outside her house, Elias and 2053-Hasan vanished into thin air. By deciding not to detonate the nuclear bomb in 2023, Elias had interrupted his continuous loop of travelling back to 1890, setting up the circumstances of his own birth and ultimately becoming the commander of a new society, and thereby erased his own existence (and that of 2023-Hasan) in the new timeline loop.

Teenage Elias was persuaded not to carry out the detonation by his older self back in 1941, whose loop had been manipulated by Maplewood and Hillinghead so that he remained isolated and unloved. 1941 Elias recorded a secret message that he entrusted to Whiteman before begging Whiteman to kill him. Whiteman left Hasan a clue as to where the record was hidden. After travelling back to 2023 from 2053, she found the record and played it to teenage Elias, who accepted that he needed to sacrifice himself to save others.

So, Elias Mannix Was His Own Great-Great-Grandfather?

Yes. Which meant that he married and impregnated his great-great-grandmother – Polly Hillinghead, daughter of Alfred. To sum up: 2053-Elias travelled back to 1890 where he took on the new identity of Sir Julian Harker, married Polly and with her had a son named Hayden (“Hayden will grow up and he’ll have children, and their children will have children, and one of them will be my father”) who became a police officer in Whiteman’s department. Hayden Harker fathered a son named Daniel, who took his mother’s surname of Barber.

Danny Barber then deliberately fathered a child with 15-year-old drug addict Sarah Mannix in order to produce Elias Mannix, the subject of his own “Know You Are Loved” doomsday cult. Elias was taken into care aged four, and led a miserable unloved life which motivated him to create the KYAL or Know You Are Loved world, using the excuse of the terrible nuclear blast to rebuild and restructure society into what he believed was a better place that would bring him happiness and the experience of love, but which created a two-tier system of those who accepted his world and those who rebelled against it.

Chapel Perilous, Gideon Defoe and “The Throat”

In 2053, an anti-Mannix resistance group existed under the name “Chapel Perilous” (a literary and psychological term meaning a dangerous trap that dates back to Thomas Mallory’s 15th century work Le Morte d’Arthur, and which was also used by writers T.S. Eliot, Dorothy Hewett and various others, as well as being used to define a paranoid psychological state by philosopher Robert Anton Wilson). That group was led by Shahara Hasan, who’d lost her father and young son in the 2023 blast, and by physicist Professor Gideon Defoe (aka The Longharvest Lane dead body).  

Through investigation of “the Deutsch Particle” (perhaps named for real-world physicist and quantum computation professor David Elieser Deutsch?), defined in the show as “an abnormal neutrino trace that defied every natural law”, Defoe discovered the existence of “The Throat” – a source of temporal displacement, or as it’s described in the show, “a pocket full of weird” – that splits people into multiple states of time or essentially, time travel.

Danofgeek