Below is the complete list of Sara Cate’s Black Heart books in order. For this series, the chronological reading order is the same as the order of publication.
Publication Order of Black Heart Books
with Rachel Leigh
About Black Heart
Sara Cate’s Black Heart series, co-written with Rachel Leigh, is a two-book dark romance sequence built around Iris and the Black family, a dangerous group of assassins whose relationships become as unconventional as the world they inhabit. The duet consists of Four and Five, and unlike many interconnected romance series that change couples between installments, these books tell one continuous story. The second novel directly develops the relationships, revelations, and conflicts established in the first, making publication order essential.
Four begins with Iris losing almost everything in a violent attack. Before her father is killed, his final instruction is simple: find Silas Black. With nowhere else to turn, Iris follows that direction and enters the household of a man prepared to help her pursue revenge.
Silas is not alone. His sons, Gabriel and Baron, are part of the same violent world, and each responds very differently to Iris’s sudden arrival. One is openly hostile, another is strongly attracted to her, while Silas feels an increasingly protective attachment to the young woman placed unexpectedly in his care. What initially brings Iris to them is survival and revenge, but her position within the Black household gradually develops into something much more complicated.
The title Four reflects the central unit that forms around Iris, Silas, Gabriel, and Baron. Rather than choosing one man, Iris develops separate emotional and sexual relationships with all three. The resulting why-choose dynamic is deliberately taboo, particularly because the men belong to the same family. Tessier and Leigh combine that relationship structure with assassins, criminal violence, age-gap elements, jealousy, revenge, and characters whose ideas about loyalty operate far outside conventional boundaries.
Five continues the story after Iris has fully embraced the Black family as her own. She, Silas, Gabriel, and Baron have established a life together while also functioning within their dangerous profession. Their unconventional arrangement may have found a degree of stability, but that stability is threatened when one member of the family leaves on what should be a straightforward assignment and fails to return.
The search for him exposes more of the Black family’s history and introduces new connections that complicate the foursome created in the first novel. Gabriel’s past becomes particularly important as the investigation moves into criminal territory beyond their immediate circle. The title again signals a change in the central relationship: the established four are confronted with the possibility that their family may have room for someone else.
That expansion is what distinguishes Five from a simple continuation. Instead of merely repeating the jealousy and attraction of the first book, it examines whether a relationship already dependent on unusual compromises can survive another major change. Family secrets, kidnapping, organized crime, assassinations, and competing loyalties supply the external suspense while the characters renegotiate what belonging to one another actually means.
Both novels are firmly adult dark romance. Their content includes graphic sexual material, violence, murder, torture, abuse, coercive situations, age-gap relationships, and other deliberately transgressive elements. The assassin storyline gives the duet a stronger romantic-suspense component than many of Cate’s later kink-centered books.
Four and Five ultimately function as two halves of the same story rather than independent romances. Four creates the Black family around Iris; Five tests and expands it. Read together, they form one of the more unusual entries in Sara Cate’s bibliography, combining revenge and criminal suspense with a why-choose relationship whose definition of family becomes progressively less conventional.