The fourth season of .

From time immemorial to the age of space colonization, there is one legend that has stayed unchanged in every history book—the tale of the immortal bird Phoenix. A being whose blood is said to grant eternal life or wisdom, the radiant figure ensures the continuation of sentient life in the universe as it oversees human civilizations and their development. Yet, mankind remains a slave to its habits; from happiness and sorrow, to wrath and love, a myriad of emotions continue to play an integral part of human life. Simultaneously, time and time again, certain beliefs and agendas persist over the centuries to disturb the fragile equilibrium of the world's preordained nature and principles. It appears that fate and its dynamic variables can manifest itself in many ways—and oftentimes exhibits a bizarre sense of humor...

Episode 11.5 of Train to the End of the World

An ordinary high school student named Bon becomes part of a team of time-traveling agents tasked with saving people's lives during historical events that happen across different eras and locations around the globe.