The sequel, The Silver Dream was released April 23, 2013. The author credits are somewhat muddled, but it was essentially written by Mallory Reaves (Michael Reaves' daughter), as the elder Reaves was battling Parkinson's disease and was too ill to write it, and Gaiman was too busy. This book revolves around Joey Harker once again, however he and his team meet a mysterious girl, who calls herself Acacia Jones. After going on a mission to save a new Walker, and retrieve data from the clutches of Binary the plot thickens.
A third volume, Eternity's Wheel appeared in 2015, once again written by Mallory Reaves (despite what the credit salad may say).
This book provides examples of:
- Acid-Trip Dimension: The world inbetween universes is described as this.
- Alternate Universe: Hundreds of thousands of them, from slight shift of timeline (where Joey dies from a dare) to the evolution of human beings being different.
- And I Must Scream: The Walkers used to fuel HEX ships are still alive and conscious, despite being reduced to almost nothing.
- And the Adventure Continues: The book ends with Joey and his team becoming official members of InterWorld and leaving on their next assignment.
- Because You Were Nice to Me: Hue helps out Joey because Joey saved its life in the beginning.
- Big Bad: DogKnife, leader of Hex army.
- Butterfly of Doom: Only major changes cause new realities to form, but major changes can be caused by seemingly minor actions. As described in the book, if a butterfly can eventually cause a hurricane, then stepping on the butterfly before it can flap its wings might be enough to split reality.
- Chekhov's Skill: The winged Joey can use her wings to slow herself and someone she is carrying down while falling, even if she's on a world where she can't fly.
- The Chosen One: It turns out that all of the Walkers are the Joeys from different realities, even the ones that are older or women.
- Cyborg: One of the Walkers comes from a world where everyone is cyberized at birth.
- Depth Deception: Due to existing beyond the usual 4 dimensions, nobody can be certain just how large MDLFs are. For example, Hue is mentioned to either be the size of a housecat from 2 feet away, to the size of a skyscraper from several miles away, to the size of the state of Vermont from several thousand miles away.
- Eldritch Abomination: The multidimensional life forms (aka MDLFs or mudluffs).
- Evil Versus Evil: Neither Hex nor Binary remotely resemble good guys.
- The Fair Folk: Fairy tales are based on beings from Hex.
- Fantasy Kitchen Sink: Thanks to creatures from Hex popping into Joey's Earth on occasion.
- Fluffy Tamer: The first thing Joey does in the In-Between is make friends with a MDLF, which he names Hue.
- The Greys: The stories are caused by the Binary making incursions into the world.
- Hyperspace: Used to travel between realities and where InterWorld is located.
- Laser-Guided Amnesia: InterWorld is able to selectively wipe the memories of people who leave.
- Magic Versus Science. The plot of the book. Basically the empire of science (the Binaries) is at war with the empire of magic (Hex) and both are trying to take over all realities.
- The Magic Versus Technology War: A war that has been going on for a long time. However, most realities are non-aligned regardless of where they fall on the spectrum.
- Mark of the Beast: The Mook Scarabus is covered in tattoos, which he presses to summon whatever the tattoo depicts.
- Me's a Crowd: Well, they're all from an Alternate Universe, but they're all the same person.
- Meaningful Name: Hue is named so because he communicates via shifting colors.
- Mind Wipe: InterWorld cadets who wash out have their memories erased before being sent home.
- Mirror Character: Hex and Binary have the same goals, abilities, and treat humans like animals. For example, one Hex wants to boil down the Walkers' bodies until only their soul are left; the other wants to slowly drain out his energy over the same period while keeping him in cold storage.
- Mr. Exposition: The mooks like to describe their plans in detail to characters who should already be familiar with what's going on.
- Multiple Reference Pun: The two opposed factions are named Binary
and Hex. - No Sense of Direction: Joey has gotten lost in his own house. Turns out that it's because his brain isn't wired for three-dimensional travel.
- Painting the Medium: When Joey has his memories erased, one of the pages goes completely black.
- Powered by a Forsaken Child: The engined used by Hex and Binary are fueled by the souls of captured Walkers.
- Pragmatic Adaptation: The sequence to enter InterWorld is represented as a mathematical formula in the book, but is changed to a musical chime in the audiobook.
- Proverbial Wisdom: Jai, who is a Yogin gifted with spiritual powers. Somewhat downplayed: he doesn't quote any actual proverbs, but his manner of speech is very flowery and koan-like, up to the point of being difficult to understand.
- Roaring Rampage of Revenge: When the imprisoned Walkers are set free, they destroy the ship in a matter of minutes.
- Rubber-Forehead Aliens: Some of the alternates have features of other animals, such as wings or fangs. Justified in that they come from the more magical Earths, where magic might have been used.
- Science Fantasy: Intentionally in the grey area between fantasy and soft Science Fiction
- Sergeant Rock: The head of the InterWorld military. Gruff and cold, but cares deeply about his troops.
- Sesquipedalian Loquaciousness: One of Joey's teammates speaks this way because "what's the point of having words if you're not going to use them". Even the cyborg with several implanted dictionaries has trouble keeping up at times.
- Sliding Scale Of Magic Versus Technology: All Earths fall somewhere on the spectrum (refereed to as "the arc"), with Joey's Earth being near the middle, but slightly on the science side.
- Soul Jar: HEX extract the soul of captured walkers and put it in a jar
- Soul-Powered Engine: HEX ships literally work that way
- Space Police: Well, inter-reality police, but functions in much the same way.
- The Spartan Way: How InterWorld members are trained.
- Time Dilation: Time does not pass the same way on all realities, and results in both Rip Van Winkle and Year Outside, Hour Inside. The InterWorld organization has some control over the effects when leaving the In-Between.
- Took a Level in Badass: Joey, after months of training. In addition to being physically strong, he's been taught such advanced science and math that he goes from being a remedial student to one of the best. Since this is after the Mind Wipe, he has no idea why he can suddenly do so well.
- Winged Humanoid: One of Joey's teammates has angel-like wings. Since they function by magic, they tend not to work well on the more science-y worlds.
- Year Outside, Hour Inside: When Joey returns to his world after months of training and having his memory erased, only about 36 hours have passed.
- You Can't Go Home Again: Joey can never return to his home dimension, lest HEX or The Binary track him there and attempt to take over, possibly killing his family in the process.
