In the game "Collapse Star Railroad", the unlocking conditions for the achievement "Between the Sky and You" are related to the in-game plot, character interaction or specific scene exploration.
Answer: We need to return to Liuying’s secret base to investigate to unlock the achievement.
1. First, we come to the Pinoconi map and choose the Dream Building Space.
2. Then we choose to teleport to Liuying’s secret base teleportation point.
3. After arriving at the location shown in the picture below, we click the magnifying glass button next to it to investigate.
4. After completing the investigation, you can obtain the Between the Sky and You achievement and receive the reward of Star Qiong*5.
The above is all about how to achieve the achievements between the sky and you in "Honkai Impact: Star Rail". For more game guides, please click on the source code website.