In the ancient world more than 6,000 years ago, the miserable wars between heaven and earth continued, and the defenseless human beings were driven to the brink of extinction by powerful races. At this time, the young leader Rick, who led the human race, accidentally met Huby, a young girl from Jikai. Hughby, who was abandoned by his companion, told himself the "human heart" in order to fix the fault. Ji Kai kind of girl's simplicity and sincerity made Rick gradually let down his guard and opened his heart to Hewby, and their relationship warmed up day by day. In the end, the two lead mankind to face the ultimate war, and the young girl Huby will also face the cruel choice between lovers and life. The end is coming, in 251 seconds, bet on an affectionate confession.