It's a crisp early October weekend, and business is slowing down as fall descends at the Sherlock Holmes Bookshop and Emporium and adjacent Mrs. Hudson's Tea Room. Wealthy philanthropist and prominent Sherlockian David Masterson has rented Suffolk Gardens House, where he plans to entertain his friends in a traditional English country-house weekend. As the chosen caterers, Jayne Watson and Gemma Doyle get to work preparing lavish meals and setting up Sherlockian books and props for entertainment. 

The 6th of January is Sherlock Holmes’s birthday, and lucky for Gemma Doyle, January is also the slowest time of the year at both the Sherlock Holmes Bookshop and Emporium and Mrs. Hudson’s Tea Room. It’s a good time for Gemma and her friends to travel to England for a Holmes Convention. For Gemma, the trip provides an opportunity to visit her parents. Jayne Wilson is excited about seeing all the sites London has to offer, and Ryan Ashburton just wants to spend some time with Gemma. But the trip is immediately derailed when Gemma’s father Henry recognizes his brother-in-law.

After the West London Museum suffers extensive fire damage, the shop owners on Baker Street come together to hold an afternoon auction tea to raise funds to rebuild it. Cape Cod's cognoscenti file into Mrs. Hudson's Tea Room, but the auction never happens. Before the gavel can fall, museum-board chair Kathy Lamb is found dead in the back room. Wrapped tightly around her neck is a long rope of decorative knotted tea cups. Gemma's boyfriend in blue, Ryan Ashburton, arrives on the scene with Detective Louise Estrada. But the suspect list is long, and the case is far from elementary. 

Legendary stage and movie star Sir Nigel Bellingham arrives on Cape Cod to star in a stage production of The Hound of the Baskervilles put on by the West London Theater Festival. When Sir Nigel, some of the cast, and the director visit the Sherlock Holmes Bookshop at 222 Baker Street, Gemma Doyle realizes that Sir Nigel is not at all suited to the role. He's long past his prime and an old drunk to boot. The cast is not happy, but the show must go on. Before the play opens, Jayne's mother arranges a fundraising afternoon tea to be catered by Mrs. Hudson's Tea Room. The tea is a huge success, but, when it's time to leave, Sir Nigel has gone missing - only to be found at the bottom of the rocky cliff, dead. When the police focus their attention on Jayne's mother despite numerous other suspects, the game is once again afoot, and it's up to Gemma and Jayne to clear Jayne's mother's name.

Gemma and Jayne are busy managing both the bookshop and the adjoining Mrs. Hudson's Tea Room in anticipation of the upcoming book signing with Renalta Van Markoff, the author of the controversial Hudson and Holmes series. However, tragedy strikes during the author Q&A session of the signing when a dedicated Sherlockian verbally attacks the series for disgracing Sherlock's legacy and is then publicly humiliated when the author triumphantly lashes back and gains the upper hand - that is, until she collapses on the table and is pronounced dead.

Kathleen is excited to meet three old pals of her beau, detective Marcus Gordon, while they visit charming Mayville Heights on business. But the reunion is cut short when one of the friends is killed - and the evidence points toward Marcus as the murderer. Though it seems she doesn't know all of Marcus's secrets, Kathleen is sure he's no killer. With his suspect status sidelining him from investigating the case, it's up to Kathleen and her feline partners-in-crime to find whoever is framing Marcus.

The arrival of the Janes brothers has the little town of Mayville Heights buzzing. Everyone of a certain age remembers when Victor had an affair with Leo's wife, who then died in a car accident. Now it seems the brothers are trying to reconcile, until Kathleen finds Leo dead. The police set their sights on Leo's son and Kathleen's good friend Simon, who doesn't have much of an alibi. To prove her friend innocent, Kathleen will have to dig deep into the town's history - and into her sardine cracker supply, because Owen and Hercules don't work for free....

Spring has come to charming Mayville Heights, and with it, some Hollywood glamour. The little town is abuzz because the reboot of a popular baking TV show is filming there. Librarian Kathleen Paulson is working as an advisor on historical facts for the show, local restaurants are providing catering for the camera crews, and Kathleen's faithful felines, Hercules and Owen, are hoping there is a cat treat challenge. But then Kathleen finds one of the judges dead. 

Spring is coming to Mayville Heights, and Kathleen's brother, Ethan, has arrived in town with his band, The Flaming Gerbils. But not everything goes as scheduled when one of Ethan's bandmates gets into a fight with a man interested in investing in the town. When the businessman's body is later found, Ethan's friend is implicated in the crime. Kathleen wants to help her brother by solving the case, but she has no shortage of suspects from which to choose. 

It's summer in Mayville Heights, and Kathleen Paulson and her detective boyfriend Marcus are eager to attend the closing concert of the local music festival. The concert is a success, but then one of the band members is discovered dead shortly after it. At first it's assumed the death is a robbery gone wrong, but Kathleen suspects foul play - and she's certain that she, along with her trusty side-cats, Owen and Hercules, can help solve the murder.