Tundra

Tundra is the fourth mission in Olimar's Assignment, representing the fourth day of Olimar and Louie's third trip to PNF-404. It takes place in the Distant Tundra.

Olimar's Expedition Log: Tundra Survey
This cutscene is identical to the Secret File Olimar's Expedition Log - In the Tundra -, but with slightly different subtitles.

Olimar's Expedition Log: Oak Survey
After completing the mission, an additional video log taking place at the Formidable Oak plays:

This cutscene is identical to the Secret File Olimar's Expedition Log - At the Oak -, but with slightly different subtitles. The ending black screen was also added.

Synopsis
In relation to the Story Mode, this day takes place before Brittany and Alph have landed in the Distant Tundra for the first time, as Olimar mentions he no longer has the Anti-Electrifier, which he buried in the snow near Charlie's crash site.

The ending cutscene takes place outside the Formidable Oak, and alludes to Olimar's disappearance. After this, Louie assumedly traveled back to the Twilight River somehow and got captured by the Scornet Maestro. This means all of Olimar's Assignment must have took place, at the very least, before the Koppaites discovered Twilight River. Given the Anti-Electrifier's placement, it's likely all days take place before the Distant Tundra is discovered.

During gameplay
In some situations during gameplay, Olimar or Louie will leave a comment.