Welcome to the next few answer arcs. Well actually technically this arc that started from episode 2 is anime only. It was created solely to put in alot of the more important details and clues that were left out of season 1 that contribute to solving the mystery. I guess that's the awesome convenience of being a time loop story.
Even with this being an anime only arc.. it is an official introduction to Rika as the true main character of the story. It really does suck to be stuck in a constant cycle of the tragedy of June 1983 and the anime does a good job getting across the constant sense of dread and despair. Hope you enjoy the answers and conclusion to the original story.