While other subplots involve Jeff (Jeff Pierre) attempting to recruit Tom (Michael McGrady) to help in his investigation, Luke (Jonathan Whitesell) getting expelled from college, and Willa (Dilan Gwyn) learning more of grandfather's secrets involving her parents, the real focus of "Celeste" is to introduce Holden (Burkely Duffield) to Charlie (Eden Brolin). It's obvious (at least to the audience) that Charlie can't be trusted, but even through her charade you can see there is some genuine appreciation for Holden and the life her organization wants to rip him from.
We get no more big reveals involving Holden's hazy memories of the Realm, but Willa's subplot does provide her with unexpected information and her mother Celeste (Lara Gilchrist) and Arthur's old partner and now rival Isaac Frost (Martin Donovan) who she suspects could be her father. Given Holden's blow-up destroying the machine and stating equivocally his plans never to return to the Realm, the two spend most of the episode apart. While the show may have thrown out the old love triangle involving Jaime, it appears they have created a new one involving not one but two women our protagonist may never be able to fully trust.