In response to earlier provocation, Shibazaki is challenged with a riddle this time only he can solve in order to stop the bomb from blasting but at one condition, no one can cheat.

Five takes over the battle of wits against Nine and Twelve as Lisa tries to find her place in their group, but Shibazaki isn't happy sitting by idly.

Twelve goes off to save Lisa while Shibazaki and Hamura learn more about the Athena Plan and the Rising Peace Academy.

Tokyo is in a state of emergency as the country readies itself for the atomic bomb explosion. Will the mystery of Sphinx finally be solved?