Ninja assassins, espionage, family betrayal and medieval clan bloodshed are playing out across the Iga province in Samurai era Japan, the setting for Fair Oaks resident and award-winning author Susan Spann’s latest addition to her Shinobi Mysteries series, which she’ll read from and discuss at Barnes & Noble on Saturday, July 22.

Spann’s new novel, “Betrayal at Iga” (Seventh Street Books), which releases July 11, promises a rare glimpse into the private world of a Ninja Clan, specifically the family life of her returning protagonist, Hiro Hattori, a trained ninja assassin now working as a detective alongside his sidekick, Portuguese Jesuit, Father Mateo.

This new, Samurai style “who done it” is Spann’s first attempt to take her readers into an actual ninja province, in this case Hiro’s hometown of Iga. Hiro and Father Mateo are in Iga seeking refuge while the assassination of an ambassador trying to negotiate a warring clan peace treaty occurs. Hiro must confront his own past and family members, as the crime may or may not have been committed by his former lover, mother, or someone else.

“I get to take readers into the actual Ninja province with this book,” explains Spann. “I wanted to continue with the Hiro series but really go deeper into the more personal side by taking readers into the day-to-day life of a ninja clan to show how ninjas actually lived and trained at home. This isn’t something you get to see very often.”

Back in Iga, Hiro confronts an old flame who is primary suspect in the case, largely because she has opposed the signing of the peach treaty. His mother is also a potential suspect. As ninjas themselves, both women are trained assassins. In fact, Hiro and his entire family are ninjas, however, with the launch of series, Hiro finds himself on the other side of justice, permanently assigned to provide security to Father Mateo. Now, the pair operate as a sort of Japanese version of Watson and Holmes. This time, the murder hits close to home.

“This is an emotional journey for Hiro,” explains Spann, who said she spent roughly nine months researching the book in Iga in 2015. In “Betrayal at Iga,” Hiro gets to interact with his mother and grandfather, and his former lover, so it is very personal.”

Spann’s first novel, “Claws of the Cat: A Shinobi Mystery” (Minotaur, 2013), was a finalist for the Silver Falchion Award for Best First Novel. The novel launched the Hiro and Mateo crime-solving adventures, loosely modeled on the traditional mysteries of Sherlock Holmes, in which paired detectives with seemingly opposite backgrounds, personalities and cultural DNA, work in tandem to get to bottom of the latest caper.

Spann is at once a transactional attorney with a private practice focused on business and publishing law, and an award-winning novelist with a degree in Asian studies from Tufts University. Originally from Southern California, Spann says she wanted to be a writer since she was a young girl, hooked initially into the mystery genre by the Nancy Drew, Hardy Boys and Agatha Christy works, as well as James Clavell’s “Shogun.”

“This is just a genre I’ve been in love with forever,” she said. “All the time growing up I wanted to write,” Spann said. “I was drawn to the mystery novels I read as a young girl, but later I really got hooked on the genre after reading ‘Shogun.’ That book really inspired me.”

Spann has already signed her next book deal in the Shinobi series: “Trial on Mt. Koya,” which she said picks up where “Betrayal” leaves off, which has Hiro and Father Mateo sent to deliver a message to a Buddhist Priest in Koya. In preparation for the forthcoming series addition, Spann spent several months living in a Buddhist temple in Koya, where she said she was granted wide access to historical information and important details about the Buddhist priests in the region of the era.

“Researching the next book was a wonderful adventure and I am very excited for the upcoming release,” Spann said.

Spann’s other works include “Blade of the Samurai,” “Flask of the Drunken Master” and “The Ninja’s Daughter.”