Shuffle Memories is a recap of the original series with an extra episode.
This episode introduces the audience to the entire cast of characters and a little of the back story for the main characters. It's a basic overview of the Shuffle! story and universe.
Kaede's story is explained from when she and Rin were kids to when they are in high school.
Asa's story involving Rin is explained from how they first met to when Asa health starts deteriorating in high school. A bit of Asa's backstory with her mother Ama is touched upon as well.
Nerine's story is explained during the time that she got to know Rin up to the point where it seems that Sia and Rin are about to be wed.
Sia's story is explained from how she first met Rin as a child to the point where rumors start about them getting married soon.
Primula's story is explained from how she first met Rin in the arcade to the point where Rin gave her a new cat doll. The time when the Rin and his friends went to the beach is briefly explained as well.
The rest of Kaede's story is explained from the point where Rin started seeing more of Asa to after Rin decided to move out of Kaede's house.
The rest of Asa's story is explained from the point when Rin and she have their first date to when Asa finally used her magic to save Rin's life.
The rest of Nerine's story is explained from the point when Primula was taken back to the demon world to when Nerine told him about Lycoris.
The rest of Sia's story is explained from the point when Kikyō and Rin go on a date to when Sia finally confesses her love to Rin, but Rin already likes Asa at this point.
The rest of Primula's story is explained from the point when she returns to the human world healed to when Rin has already moved out of Kaede's house.