What makes for an excellent fiction series? For that matter, what defines a series?
Persistent characters who develop over multiple stories. Conflicts, drama and story arcs that span multiple books. Story-critical concepts that underpin the series, be it magic, high technology, forensic science, and so on. Exploration and expansion of these concepts to facilitate the plot. The expectation that each successive book builds upon the previous one, creating a chronologically-coherent timeline. To make a series work, you must maintain internal cohesion by ensuring that events occur in a logical fashion, that characters act and react in a manner consistent with their previously-established personas, and that existing concepts are built upon and new ones signalled or gradually introduced.
Sean Chercover’s Daniel Byrne series is an excellent example of an incoherent series.
The series begins with The Trinity Game. Daniel Byrne is an investigator for the Vatican’s Office of the Devil’s Advocate, which studies alleged miracles. He has never found proof of miracles–until one day, his uncle Tim Trinity, begins predicting the future. Trinity is a con man–but is he telling the truth this time? As Byrne investigates Trinity, secret organizations step out of the shadows, including the Mafia, the Council for World Peace and the Fleur-de-Lys Foundation. Caught in a shadow war, Byrne must protect Trinity as he prepares to deliver a final prophecy his enemies will do anything to prevent.
The series begins with a promising start. A compelling protagonist who presents himself as a man of God despite not believing in God. A con man who may or may not be running a con. A power struggle between powerful and ruthless factions for the fate of the world. The sequel The Devil’s Game builds upon these core ideas. Byrne has now joined the Foundation, and discovers a strain of the plague that grants its victims the power of foresight. He partners with disgraced doctor Kara Singh, who suffers visions of her own, to trace the source of the plague–and discovers a conspiracy to release a world-changing pandemic.
So far so good. The conflict between the Foundation and the Council escalates in the second book. Byrne has apparently found his life’s purpose, and someone to share his life with. The true faces of the Foundation and the Council are revealed. And a shocker in the final chapter sets the stage for the third book, The Savior’s Game.
Which crashes and burns.
The Savior’s Game is not a bad story. It’s an exceptional novel. Byrne is forced to work alone, relying on his wits and his best friend. He has to navigate a strange new world with even stranger powers, while pursued by enemies far deadlier and more capable than before. As a standalone book, it is incredible. But as the conclusion of a trilogy, it fails.
The central conceit of the series is Anomalous Information Transfer, an unexplained ability to experience the past, present or future as visions. The Council wishes to control it to rule the world, while the Foundation aims to stop the Council. This meta-conflict between the Council and the Foundation suddenly vanishes in the third book, never to be seen again.
Replacing AIT is a surreal world called the Source, a deeper reality underlying this one–one that has never been hinted at in previous stories. There are allegedly thousands of inhabitants in the Source, but there are no indications in previous stories that people who experience AIT aren’t simply experiencing visions, or that there are people who can transport their consciousness to another plane of existence. AIT and the Source come off as two distinctly separate phenomena, linked only by the most tenuous of plot threads.
The main antagonist of The Savior’s Game is a character from the second novel who was mysteriously resurrected, but there are no explanations why this occurred or what happened to other dead people.
A secondary antagonist, revealed near the end, is a traitor, a character who has appeared in the previous novels and now claims that he agrees with the primary antagonist and wants to burn the world down–but up to that point, there is no sign that the traitor has embraced nihilism or even had any contact with the main antagonist.
With the critical elements of *The Savior’s Game* so profoundly disconnected from the rest of the series, it comes across as the conclusion of a completely different series altogether. To avoid the same fate, you must maintain cohesion in your fiction series. To do this, apply the concept of anchoring.
When a reader reads an earlier book in the series, he has built an image of the characters, story world, key conflicts and conceits in mind. He knows what kind of people the characters are, how the world works, the conflicts that drive the story, and so on. This knowledge anchors him to the ideas that define a series, *and* creates the expectation that future books will build upon this anchor.
In future books, characters must act, react and grow based on the events they experience in the story *and* how previous events have shaped them. The world must evolve in response to the events in previous books. Conflicts established in previous stories must advance or end. The reader must be able to draw a clear thread linking events and character evolution from previous stories to the present.
If you want to introduce new concepts, you must do so in reference to the anchor — that is, it should build upon what the reader already knows of your story. If you want to introduce a super advanced faster than light drive in the second book of a series, then in the first book there must be references to starships and spaceflight to ground the reader in your story conceits. If you want to have a wizard flinging around ultra-cool magic in a later book, then in earlier books you need to establish the existence of magic, and possibly any principles said wizard will use for said ultra-cool magic.
If you must bring out completely new ideas that have no previous reference points, you need to prime the reader to expect new concepts to come out of nowhere. In Jim Butcher’s *Dresden Files*, every faction has its own unique brand of magic: necromancers bring the dead back to unlife, White Court vampires feast on lust, Red Court vampires drink blood, the Denarii are fallen angels, the Knights of the Cross are holy warriors, and so on. This primes the reader to expect a a new kind of magic whenever a new faction or monster is introduced.
Every book in a series should have anchors for readers familiar with previous books, the better to prepare them for the novelties to be introduced in the current book. Harry Dresden is the key anchor for the Dresden Files: he pits his already-established magic powers against these new and unknown foes and their abilities, creating a sense of familiarity and cohesion for the audience, and when Dresden develops new powers, his research and development is explicitly shown on the page, priming the reader for their appearance.
If you’re writing a closed-ended series, one with a definitive ending, there is another trick you can use: plan the ending of the entire series before starting it. Once you know the beginning and ending of the series, how the major conflicts will be resolved and how the characters will meet their fates, you’ll be able to plan how each installment in the series builds upon each other. This prevents new ideas and stories from disrupting the series and turning it into something that isn’t.
If you expect a series to end in a dramatically different manner from the expectations established in the first book, you should signpost this divergent ending where possible. The Dresden Files series appears to involve Harry Dresden taking on seemingly unrelated cases, but in several stories Dresden determines that there is an unseen faction who is secretly pulling the strings — although he hasn’t, as yet, uncovered their motives or leaders. This hints at the (possible) ending of the series: a final showdown between Dresden and this faction. Signposts like these tell the reader that while they can enjoy the current story and series in their present form, they should brace themselves for the series to take a different turn.
Cohesion is critical to creating a successful fiction series. In each successive installment, anchor your readers in the story world so you won’t lose them when introducing new concepts. End the series in a way that flows organically from its beginning — but if you must take the series in a new direction, be sure to signal it as early and as often as you can.
In my own novel, No Gods, Only Daimons, I signposted the ending of the series in the climax. Good luck finding it!