When restorer Lin Yu was renovating an old pocket watch from the Republic of China, he accidentally triggered the time and space mechanism in the watch and was involved in the old alleys of the concession in 1937. In that era of early war, he met Su Tangtang, a self-proclaimed "Time Observer" - a girl who could briefly freeze time with her thoughts, but was tracked by a mysterious organization because of her frequent use of her abilities. Every three rotations of the pocket watch's pointer will force the shuttle channel to open. Lin Yu must find a way to repair the pocket watch and control the shuttle within a limited time, otherwise he will be trapped in the past forever. The existence of Su Tangtang seems to be inextricably linked to the disappearance of the original owner of the pocket watch and the "Time and Space Correction Plan" of the mysterious organization. When Lin Yu discovered that every time he travels through time and space, causing small changes in the past to backfire on the present, he had to make a choice between saving Su Tangtang, protecting his own time and space, and uncovering the centuries-old secret behind the pocket watch. Two people from different eras, whose fates were intertwined because of an old pocket watch, embarked on an adventure racing against time in the gap between time and space.
