At Yanari's party, Nai and the crew deepen their friendships and experience the warmth that comes of supporting and encouraging one another. Upon their return to the 2nd Ship, Gareki is summoned to meet with a stranger, who has come aboard disguised as a tree...?!But back at Chronomé Academy, Kafka launches an attack, sending a swarm of Varuga to lay siege to the prestigious school. And when Tsubame attempts to protect her friends...she ends up a hostage herself! With Gareki back on board the 2nd Ship, who will come to her rescue?!