#also it ended up not even being about sentitwins i just went full in

[bittersweetresilience]

talking to both @keeperofthebox and @moonieratty today somehow combined into me cooking up a sentitwin infinity train au where one twin is the reflection of the other

specifically, félix (lake) has been living as adrien's (tulip's) reflection for their entire lives. when adrien boards the train, félix realizes he has an opportunity to escape. he double crosses adrien when he enters the chrome car and switches their places, but they ultimately reconcile and switch back. adrien sets félix free from the mirror world so he can be his own person and they separate.

félix meets kagami (jesse) and duusu (alan dracula) while on the run from mirror police. kagami is dealing with her own perfectionism and familial reasons for being on the train. they help each other with their problems, overthrow the tyrannical chrome car state, and figure out how to get félix a number so they can both leave the train and be together in the real world. they run into chloé and lila (grace and simon) on the way.

meanwhile, after helping félix escape, adrien continues his own adventure in navigating his emotional repression, father's disappearance, and mother's death. his primary companions are tikki and plagg (one-one), who used to be conductors of the train. they were secretly ousted a year ago by gabriel (amelia), who is mad with grief and trying to create a car to bring émilie (alrick) back. this significantly complicates adrien's cathartic journey, especially because nooroo (the cat) is interfering with him on gabriel's orders.

finally, adrien confronts gabriel in the conductor's car over how to cope with grief. while adrien succeeds in restoring tikki and plagg to their rightful position and leaving the train, gabriel has dug his own grave and is left behind to make reparations or die.

sometime afterward, chloé and lila have an adventure of their own, wherein meeting zoé (hazel) changes the progression of chloé's life.