It's mainly about the adventures and challenges of the dragon characters in the Wings of Fire series. It might include their battles, relationships, and growth within their dragon world.
Since it's the fourth in the 'Wings of Fire' graphic novel series, it probably builds on the existing plot. It may focus on a particular dragon or group of dragons and their journey. It could be about their struggle for power, their search for a new home, or their attempts to solve a mystery that has been plaguing their kind. There may be epic battles, deep emotional moments, and revelations about the true nature of the dragons and their place in the world.
I don't know specifically for this fourth one. But in the 'Wings of Fire' series, there are often dragon characters like Clay, Tsunami, Glory, etc. Maybe the main characters in this graphic novel are descendants of those original characters or new characters that are related to the overall plot of the series.
In the " Chronicles of the Wings ", the disappearance of the last day of April meant that the entire story world had undergone a huge change, making every time point on the Timeline no longer accurate. This change was called a "time jump". It happened in the future of the story, so the entire story world experienced the result of time jumping.
After the time jump, the characters and things in the world changed, including the way time passed, the development of history, the time in reality, and so on. Therefore, the disappearance of April 1st was to reveal these changes and show the complex effects of time jump.