Mari Tamaki, AKA Kimari, really wanted to have a great adventure in high school, but could never take the first step. Now in her second year, she meets Shirase Kobuchizawa, a girl who is determined to go to Antarctica despite being told it's impossible. Kimari is so moved by Shirase's indomitable spirit that she vows to go to Antarctica with her.

To get on a ship to Antarctica, Kimari and Shirase will first need the money to fly from Japan to Fremantle, Australia. To earn this money, Kimari gets a job at a convenience store, where she meets a girl named Hinata Miyake. Hinata decides to join them on the trip, and quickly gets swept up in Shirase's next plan...

Kimari, Shirase, and Hinata need to figure out a way that high school girls might be allowed to go to Antarctica. Although dubious about their chances, they quickly find a report about a high school-aged actress named Yuzuki Shiraishi, who's being allowed to come along. Shirase attempts to make contact with Yuzuki's agency, but it just so happens that Yuzuki has come to them.

Kimari and the others finally have their tickets to Antarctica. However, they'll need to go on a three-day summer training camp to learn the skills they'll need. In the mountains, they experience everything from lectures to field work, and meet the team commander, who seems to have a history with Shirase.

It's been several months since their training, and the girls' trip to Antarctica is drawing near. With Rin's help, Kimari manages to sort out her luggage, and in doing so, finds a game she borrowed from Megumi a long time ago. When she visits her friend to return it and talk about old times, though, Megumi doesn't seem to remember it at all...

The girls have a stopover in Singapore on their way from Japan to Fremantle. They decide to spend their time sightseeing, but Yuzuki notices Hinata acting strangely.

After arriving in Fremantle, the girls get a tour of their icebreaker ship. When Gin mentions that their new room was where Shirase's mother once stayed, the girls check to see if she might have left something behind there...

The ship sets out from Fremantle, heading for Antarctica. The girls interview crew members, peel potatoes, and get training to improve their stamina. But as exhausted as they are already, an even greater disaster awaits them!

Expedition member Toshio confesses his love for Gin, and asks if Shirase knows anything that might help him get closer to her. Shirase tells him that Gin was just a friend of her mother's, so the girls insist that Shirase go to talk to Gin herself.

When the girls are testing a video connection to Japan for New Year's, a few of Hinata's "friends" come calling. Hinata begs off, but seems distracted for the rest of the day. Shirase decides to get to the bottom of things.

Ever since her mother was lost in Antarctica, Shirase has felt like she was lost in a terrible dream. Despite her fear of what will happen if nothing changes after she goes, she and her friends now set off on their final journey to the place where her mother was lost.

Kimari wakes up to the sound of her alarm and goes through her duties for the day. The girls have gotten used to their lives in Antarctica, but the summer team will have to leave in three days. Their journey of a lifetime is reaching its end.