I just read a Chinese translation of the prologue.
Spoiler for Short Summary:
-Headmaster Rick announces the end of the semester
-Glenn walks lazily through the hallway and meets Eve. Glenn asks Eve what she is going to do in the vacation. Eve is going to prepare herself to teach students about military training next semester. They kept walking while saying nothing until they reached Glenn's class. Eve then tells Glenn that if he's busy in the vacation he needs to work hard on them. This causes Glenn to ask what she means. Eve then left.
-In the classroom Class 2 is talking about what they are going to do in the vacation. Some are studying, others are traveling and some are working.
-Glenn thinks about what he's going to do in the vacation. He feels lost, because he's been so busy at school that he doesn't know what to do now that he doesn't need to do anything. He starts wondering about what Celica is doing since he didn't meet her since the Three worst days of Fejito. He then decides to study the notes he got from Alicia III/Mabel. However the usual trio (Sistine, Rumia and Re=L) appears before him and ask him if he could accompany them in the travels during the vacation since their parents are never home, because of work.
-We cut through what happened last night. They are all in their pajama's and Rumia has a serious expression on her face, because Eve is currently a dangerous enemy and in the worst case scenario she may get Glenn if they sort out their problems. Rumia also says that Glenn doesn't see them as women, but only as students. This causes them to ask Glenn to accompany them during the vacation, because they need opportunities outside of the school so that Glenn can't see them as students.
-Glenn then thinks about what Eve said and accepts their invitation. Sistine is happy he accepted so easily, but Rumia isn't, because if he's able to accept it so easily it means he doesn't see them as women.
-However suddenly a bigger enemy appears. It's Celica with travel gear and baggage, she immediately hugs Glenn. This causes Glenn to complain about how clingy Celica is. Celica also says he's going to travel with her now. Glenn is confused about how sudden this is.
-Meanwhile Sistine and Rumia are watching what unfolds and promptly forget about the dangers Eve possesses and realize that they forget that Celica is truly the bigger enemy, because she's treated as a woman by Glenn, closer to Glenn than anyone else, is familiar with the people Glenn knows and they can't defy her, because she still is one of the most powerful magicians of the world despite losing some of her magical talent in Volume 6.
-This causes them to accompany them during their travel to the Snoria region.
Okay this is the first summary I made. I'm not sure how good my English Grammar is to be honest.
I also have to say that Rumia is currently working the hardest to get Glenn. She's already planning and scanning the amount of danger her opponents possesses.