I want to make it clear that if you did not see the movie this will be a spoiler for you
A strange character dressed as a rabbit who responds to Frank's name appears one night in the garden of Donnie's house and calls him out. Donnie obeyed, thus saving himself from the artifact that was destined to end his life that very night (an artifact of an airplane, which will later be unreachable, falls right into Donnie's room).In the moment in which the protagonist mocks to the death, it creates the tangent universe or parallel reality, the reality that does not have to happen. You will recall that Frank points to Donnie the time left for the end of the world, 28 days, 6 hours, 42 minutes and 12 seconds. Indeed, that is the time when the world in which Donnie is found must be destroyed, that is, the parallel reality. The tangent universe must be destroyed so that the primary can continue coherently over time.
Frank has the mission to make Donnie accept his death. For this, it causes the death of Gretchen (the girl of whom Darko falls in love in this parallel world). At this point, the protagonist understands what he should do. If it causes its own death, the parallel reality will never be created, it will not be able to know Gretchen and this one will never die.
Roberta Sparrow, commonly called Grandmother Death, is the crazy old woman who looks at the mail continuously. She is the writer of the book The Philosophy of Time Travel with which she is obsessed Donnie explains everything that is happening (creation of a new universe, ability to travel in time, to be able to see the future ...). This book provides the fundamental keys to understanding the film.
Chain of events that will destroy the tangent universe: Frank forces D to flood the institute → D. knows Gretchen. The flood also causes the crazy gym teacher to call the famous therapist Jim Cunningham to go to school to give talks of love and fear.
Frank causes D. to find Cunningham's pussy wallet and forces him to burn his house → in this way he is discovered to be a pedophile → The gym teacher collapses and decides to stay in the village to defend Jim instead of traveling To New York with the dance group of the institute → In this group is the little sister of Donnie, reason why the mother of the protagonist will be the person in charge of the group and will travel with them in airplane → the device that will end definitively with the life of Donnie and all this paranoia comes from the plane where his mother and sister will travel back. I mean, Darko provoked everything. All this happened in 28 days, 6 hours, 42 minutes and 12 seconds.
