Mash, Castoria and Ritsuka are tasked with dealing with a Singularity located on a deserted island with strange ruins, however as they arrive, the communication with Chaldea is lost. They have 100 days to resolve it, so they quickly get to work.

Ritsuka was now searching on the beach for a good place so they could rest while searching for a place to live.

While he was doing this, Mash and Castoria went into a forest nearby to search for food without going too far.

The 3 were sent to this deserted island because a Grail was discovered and strange creatures started to born from this Singularity. As they arrived however, communications with Chaldea were lost, but Da Vinci managed to state 1 thing before she was cut.

"You have 100 days to find the Grail to destroy the Singularity" -

100 days, simple enough, but now they also need to find whatever is blocking the communications and remove it so Chaldea can retrieve them.

After a few minutes, Ritsuka found a cave away from the beach so the water didn't get inside. With that, he then decided to go search for Mash and Castoria.

Going inside the forest, he quickly found the two, who were carrying the corpse of a moose on their shoulders.

"Senpai, we found some food" - the pink girl kouhai said smiling.

"Great, I'll make some fire so we can cook it and eat something" - Fujimaru answered while the three started to make their way back to the beach.

Ritsuka showed the two girls the cave he found and said that they could live there until they found a place to build a house, to which the two girls agreed. After that, Ritsuka collected some tree branches and made fire to cook the moose.

As the creature was cooking, Castoria excused herself and went outside to take a look at the blue waters of the sea that surrounded the island. Like a little girl, she started to play, splashing in it while laughing as the night started and when the dark arrived, she returned to the cave, finding Ritsuka and Mash eating.

"Why didn't you wait for me?" - the girl asked while pouting, which both found cute.

"Sorry, we just got hungry. Sit next to me, I'll pass you a piece" - Ritsuka said while smiling.

Castoria did so, but as she was sitting she noticed Mash leaning over Ritsuka¡s shoulder and resting her face there while humming a melody she didn't know. This made her jealous.

Even if Ritsuka didn't know, the girl had feelings for him. As she was based on her counterpart from the Sixth Lostbelt and had her memories, she remembered what her happiest day was.

The walk on Gloucester with Ritsuka on the 11th, the only moment where she walked with someone she loved.

Originally, she was going alone with Ritsuka on this mission, but a few hours before they left, Mash convinced Ritsuka to allow her to travel with them in order to protect both of them now that she had an upgrade, which made the blonde girl angry, though she didn't say anything.

Now, the three were trapped in this island for 100 days, and while she planned on doing her mission as fast as they could, she also planned on using the time to build a stronger bond with her Master. Problem? While she didn't know, Mash also had the same idea as her.

"Why do I feel like this trip is going to become something dangerous?" - Ritsuka thought to himself, but for the moment decided to ignore it as he ate with both girls.

Their adventures on the island were barely getting started...