The kids were exited for the sun to come out because they don't remember it when it came out 7 years ago.
On Venus the sun comes out every 7 years and when it is not out it is raining.
The classmates didn't like Margot, who was always alone and sad, so they pushed and locked her in a closet.
Then all the kids saw that the sun came out. They were all very exited because they don't remember the sun from the time it came out because they were only 2 years old.
All the kids went out to play in the sun and have fun while it lasted.
Then when the kids came inside because it started to rain again, they remembered that they left Margot in the closet and felt bad. They went to let her out of the closet and were felt very bad for leaving her in there.