I just finished watching this and it left me feeling a bit annoyed. I suppose viewers are left to put the pieces together since they didn't do very much explaining. I suppose the siblings were given to them as the ones who must be repeatedly sacrificed every 21 years for continuation, since the parents clearly knew the deal involved losing them to a time when their lives will be sacrificed. They tried to prevent it from happening by hiding the truth but only did more damage in the end. The mother struck a new deal with the Hare God that set in motion Jakoob to do his bidding and that came at a cost to get Ida to the Island. One of the many holes, was the teacher the actual Hare God or just another servant. If he was, why go through the trouble for the Island in the first place, when he was the there the entire time. So Hare got angry when Ida killed her baby and took the classmates along with her.. Then theres Astrid the next cycle that must be sacrificed 21 years after, why else forget about you're own child and care more for a sibling? Was is just a coincidence, or was it another set up for another sacrifice.. it's a mystery. What I do know is the show could have been written much better.. Instead we get a storyline about a sister on the neverending 21 year cycles of the equinox forgetting about her life + child to go on a (slow & choppy written) journey to find her sibling after the initial 21 year cycle we see and reunite with eachother in the end of her own 2nd 21 year cycle