Mari Tamaki is an adventurous teenager aspiring to accomplish many things during her youth. However, the fear of failure causes her to constantly back out at the last minute. Although she is already a second-year high school student, that has not seemed to change. That is until she crosses paths with Shirase Kobuchizawa.

Shirase's mother was an explorer who went missing during her trip to Antarctica. In order to find her, Shirase has worked relentlessly in part-time jobs to save up the funds to join the civilian Antarctica expedition. Despite her classmates ridiculing Shirase's dream for being nonsensical and unrealistic, her desire to find her mother remains steadfast.

Moved by Shirase's determination, Mari decides to join her. Soon after, their passion inspires two others to join them: Hinata Miyake, a sociable girl with an inquisitive personality; and Yuzuki Shiraishi, an elegant girl who has had little experience with friendship. As the four girls embark on the journey of a lifetime, they start to grow closer than ever before.