Even during summer vacation, lone wolf Horikita would rather remain locked in her room studying than interacting with others. One day, Ayanokouji invites her to visit the pool with some of the others.

All students go to the cruise. Chabashira informs Kiyotaka that somebody requested his expulsion. If he don't help others to promote to A class she will use first opportunity to expel him.

As part of a special test, the school has brought the students to an uninhabited tropical island where they must now live for a week. Their performance on the test can have an enormous impact on the point standings of the four classes.

Class D has achieved a degree of unity in facing the special test, so Ayanokouji and Horikita head out to see how the other classes are getting along. Class B is working together to make a comfortable life for themselves, while Class A remains secretive.

With the panty thief incident already eroding Class D's trust, Horikita finds her leader key card stolen. While they try to figure out who did it, the base camp is thrown into chaos with a new incident of arson.

Survival test is coming to the end. Things don't look well for 1-D. Key card is stolen. And now Suzune is forced to withdraw due to her sickness. Kiyotaka will try to turn things around.

As the sports festival comes down to the wire, Horikita must deal with Sudo, as well as Ryuen's threat.

Horikita decides to use Paper Shuffle to settle matters with Kushida, and Ayanokoji finds himself caught in the middle.

As the day of the Paper Shuffle draws near, the plans of the various forces in play collide.

Ayanokoji receives a visit from outside the school, and learns more about the conditions of his stay.

Karuizawa, whose cooperative relationship with Ayakoji has ended abruptly, cannot hide her embarrassment at the complete loss of contact with him. As Class D discusses their plans for the future, Ryuen and the other members of Class C appear overbearing.

Ayanokoji makes his final decision on how to deal with Ryuen and the Class C threat.

The aftermath of the gymnasium incident plays out as Christmas brings romance to the school.