Hiiragi Kyouichirou is a boy who travels from his provincial town to Tokyo to attend university. He carries with him his family's sword to protect himself. When he arrives in Tokyo, he becomes swept up in a plot by the Imperial army. (Source: ANN)

With his mother taken away from him and having lost everything, Lag Seeing is now a letter whose delivery has been assigned to Gauche Suede, a Letter Bee. Despite their troubling start, the two of them become friends, leading Lag to realize what his aim in life is: to deliver people's most important feelings in the form of letters, just as Gauche has done. [Written by MAL Rewrite]

After Niche carries the wounded and stunned Lag back to the Bee Hive, the Letter Bee finally begins to piece the puzzle together. Now he knows what's happened to Gauche, why the Marauders are so focused on stealing mail and the actual intent of the group controlling both, Reverse. However, when he's forbidden to reveal the truth, Lag is soon forced out of the artificial sunlight and back into the world of perpetual night. And soon Reverse's plot to take down the Letter Bees and overthrow the Amberground government begins to accelerate. If things weren't already bad enough, the giant insect creatures called gaichuu are apparently evolving into something new; there may be traitors working within the Hive; and Niche's sister, who's definitely not human friendly, shows up to turn family drama into a full-scale siege! It all spells serious trouble for the Letter Bees, but if anyone can weather the storms and gloom of night, Lag and his team are the ones who'll deliver. (Source: FUNimation)

In the previous century, an unprecedented disaster known as the Invertia drastically reformed the world. The powers of existing nations declined significantly, paving the way for a conglomerate called the Integrated Empire Foundation to assume control. But more importantly, the Invertia led to the emergence of a new species of humans who are born with phenomenal physical capabilities—the Genestella. Its elite are hand-picked across the globe to attend the top six schools, and they duel amongst themselves in entertainment battles called Festas. Ayato Amagiri is a scholarship transfer student at the prestigious Seidoukan Academy, which has recently been suffering from declining performances. Through a series of events, he accidentally sees the popular Witch of Resplendent Flames, Julis-Alexia von Riessfeld, half-dressed! Enraged, Julis challenges him to a duel for intruding on her privacy. After said duel is voided by the student council president, Ayato reveals that he has no interest in Festas. Instead, he has enrolled in the academy to investigate the whereabouts of his missing elder sister. But when a more devious plot unravels, Ayato sets out to achieve victory, while being surrounded by some of the most talented Genestella on the planet. [Written by MAL Rewrite]