The song September Song by Jess and Gabriel tells the story of a past love that still resonates with the singer. The lyrics describe how their love was strong and innocent when they were only fifteen years old, with a mixtape playing on repeat every weekend. However, they eventually went their separate ways, and the singer now sees their face in unexpected places, feeling a sense of danger if they were to meet again. Despite the passage of time, the singer still holds onto the memories of their past love. They recall the chorus of the mixtape they used to listen to and sing along to it, hoping to reconnect with their lost love. The song expresses the wistfulness and longing for a simpler time, and how the memories of past loves can continue to linger on and impact us as we move forward in life.