Yumeko challenges Terano Totobami to a gamble for Student Council presidential election votes and they agree to play a game called the "Greater Good Game" presided over by Rumis Uru. The players agreeing to participate are Yumeko Jabami, Itsuki Sumeragi, Kaede Manyuda, Miloslava Honebami and Ibara Obami. The game involves choosing whether to place coins in a Personal Bank Box for their own gain, or into a Tax Deposit Box which will increases coins for all players. Before the first round, Yumeko suggests that everyone place all their coins in the Tax Deposit Box, but after the first round, there are only 20 coins deposited which means that there is a traitor and the recriminations begin. For the second round, Yumeko suggests that each player deposit a set number of coins as she has written on pieces of paper, but after the round fewer coins are deposited into the Tax Deposit Box than was agreed, possibly indicating two traitors may be working together. The players begin accusing each other of being a traitor, until Kaede is asked by Itsuki who he thinks is the traitor is, and he points to Yumeko.