All the previous books of the series followed roughly the same general plot. A client came to Perry Mason office with a non-trivial but also not critical problem. Mason began investigating (usually involving Paul Drake) until a dead body showed up with all evidence pointing to his client being the murderer. Mason continued the investigation while avoiding the obstacles created by his archenemy Sergeant Holcomb until the court hearing where he would finally show the truth with skillful cross-examination of witnesses.
This book signifies the departure from the formula above. For starters it contains not just Mason's POV which was the case before. Sergeant Holcomb is gone replaced by Lieutenant Tragg. This was quite surprising as Mason mentioned that he was partially responsible for Holcomb's departure - and I thought the two finally came to (reluctant) understanding in the previous book. Tragg is smarter than Holcomb and tries to cooperate with Mason most of the time. Paul Drake does not make his personal appearance, but he will be back in the next book.
Two sisters opened several flower shops.
Later when they become successful one of sisters - Mildred Faulkner began to suspect a guy who was holding a virtual monopoly on the business was trying to take over by buying off their stock.
So her part of the stack was safe, but when she checked on her sister it turned out the sister let her husband manage it. The husband could not produce it immediately and Mildred realized she needs a good lawyer - say Perry Mason - to protect her interest. Before she came to him she did her own investigation which led her to an illegal casino and its poisoned employee.
By the time Mason got involved another employee was shot with clues pointed at Mildred. To his complete surprise Mildred did not want Mason to represent her.
It was fun to see Mason closely working with police represented by Tragg for a change. I did miss Paul Drake and his attitude on life, but I am happy to say he will be back in the next book - as I already mentioned. Due to the cooperation the case was solved before it got to the courtroom, but it was complicated enough to make up for the absence of Mason's interrogation of witnesses. Even despite the fact that I was able to figure out what exactly was going on, I still rate the book with 4 stars.