“Harry Potter and the Cursed Child,” the Harry Potter play due to open in the West End in the summer of 2016, will be a two-part epic set 19 years after J.K. Rowling’s seventh Potter novel, “Harry Potter and the Deathly Hallows,” and will feature a storyline that revolves around an adult Harry and his youngest son, Albus.

“It was always difficult being Harry Potter and it isn’t much easier now that he is an overworked employee of the Ministry of Magic, a husband and father of three school-age children,” reads the summary of the project revealed by Rowling and her team of theater collaborators, director John Tiffany and writer Jack Thorne. “While Harry grapples with a past that refuses to stay where it belongs, his youngest son Albus must struggle with the weight of a family legacy he never wanted. As past and present fuse ominously, both father and son learn the uncomfortable truth: sometimes, darkness comes from unexpected places.”

The play will be presented in two full, evening-length parts. On some days of its playing schedule, “Harry Potter and the Cursed Child” will play Part I at the matinee and then Part II in the evening.

The new details of the show, which will have a cast of more than 30, come after initial announcements of the project suggested the storyline would be more of a prequel that focuses on Harry’s early years. This is also the first announcement of the fact that the show — a new play based on an original story by Rowling, Thorne and Tiffany — will be split in two parts.