A Promise by the Lake.While Irina's training progresses smoothly, there are issues in the development of the test rocket as more safety features need to be removed to meet the upcoming deadline. Korovin also is not in good health as he tries to personally oversee the construction. Irina's next training is to undergo a solitude test in a anechoic altitude chamber. Lev recommends that Irina try something relaxing before the test to better prepare for it, and she decides to accompany him to the jazz bar he likes to frequent. After having some drinks, Lev tells Irina that he was fascinated by space since he was a child...