One of the members of Kaiju Club is Nakajima Ryota, a young man who loves monsters with a passion. He is the only one who has a girlfriend Yuriko and is troubled by the ultimate choice he must make time and again – should the members or Yuriko be his priority? It is her birthday on Sunday. But that day is also an important deadline for the club. The alien Metron watches over Ryota as he agonises. What will his choice be in the end?