Here is a statement from Alastair Heim about the project from Associated Press: "
"All throughout writing the story, I couldn’t fully believe that I was actually getting to play in the amazing creative sandbox Dr. Seuss created all those decades ago,"
Here is another statement, this time from Aristides Ruiz:
"When I heard of the opportunity to be a part of this project, I jumped at the chance only to find that it was difficult and daunting to approach adding to or expanding such an esteemed and treasured part of the American Christmas canon."
so, here is the plot of the book sequel :
The sequel fills in the gaps for fans who may be wondering what happened in the year after the Grinch's heart grew three sizes after he embraced the spirit of Christmas.The Grinch plans to win over the rest of Who-ville by proving his love for the holiday. To do so, he sets out to win Who-ville’s Christmas Crown by "making the largest, most spectacular Christmas tree the Whos have ever seen!"
"How the Grinch Lost Christmas!" is scheduled for release on Sept. 5.
Source: usatoday.com