Darkwing (known as Dusk in the United Kingdom) is a novel by Canadian author Kenneth Oppel. It is the prequel and fourth addition to the Silverwing series, and takes place 65 million years before the events of the first book, Silverwing. It describes the origins of the war between the birds and the beasts.
The story takes place 65 million years ago, at the very beginning of the Cenozoic era. A huge natural disaster has wiped out most of the dinosaurs (referred to as "Saurians" within the context of the story), though a few have managed to survive in the aftermath, albeit weakened by climate change, a shortage of food, and a flesh-rotting virus. The mammals, who were once at the Saurians' mercy, form The Pact: unable to wage battle against them on their own terms, they decided to band together to exterminate the remaining Saurians by destroying their eggs, so that the Saurian threat will be extinguished forever.
The story revolves around a colony of proto-bats called Chiropters, which live in safety in a giant sequoia on an uninhabited island, having deserted the other mammals due to refusal to participate in The Pact, a union between all beasts to destroy all Saurian eggs to drive their disease ridden species to extinction. Dusk, a young Chiropter, is being taught by his father how to glide. Dusk is different from the other Chiropters, however; whereas his brethren have simple sails, Dusk has wings, and an urge to fly that he has difficulty suppressing. He is regarded as a freak by the other Chiropters, though he finds acceptance with his parents and his sister, Sylph. Dusk learns to fly, but keeps his secret to himself out of fear of being shunned.
Carnassial, the Felid (a type of proto-cat) also has a hidden desire. Born with shearing teeth and an insatiable appetite for flesh, he seemingly fulfills the pact when he destroys the last known batch of Saurian eggs. The world is changing, and now that the Saurians are extinct, he leads a pack consisting of other flesh-craving Felids to form a new world order, with his kind as its undisputed rulers. The rogue pack of Felids find their way to Dusk's island and devour many of his colony, among them Dusk's mother.
With their island invaded by these deadly new predators, it is up to Dusk and his unique powers of flight and echolocation to find the Chiropters a new home where they can live in peace. Carnassial strikes an alliance with the powerful (but unintelligent) Hyaenodons, who claim that the Saurians do still exist, and enlist the Felids to find and destroy their eggs. Carnassial comes to realise that in order for the Felids to rule, it will have to be through cunning rather than through power.
Along the way, Dusk and his colony seek refuge with a seemingly peaceful colony of "Tree Runners", only to find out that they plan on sacrificing them to a giant, meat-eating bird; the Diatryma. After escaping, Dusk finds a new home for his follow Chiropters, but it is on the other side of a savannah, which is home to many predators. While Dusk is scouting for a good place, he meets another creature that looks similar to himself; it calls itself a bat and tells Dusk that there are many others like them.
While trying to cross the savannah, the colony encounters Carnassial and the Hyaenodons. They seek refuge inside a hollow tree, only to be attacked by horrible venomous shrew-like creatures called "Sorcids". The Sorcids overwhelm and devour a Hyaenodon, and nearly kill Dusk, but he is rescued by Sylph. While trying to cross the Savannah, Dusk gets caught in the web of a giant spider, which cuts him loose from its web. He and Sylph are attacked by Carnassial and his Hyaenodons once again, and take refuge in the skeleton of a large dinosaur. Through it, they find their way into an eerie, underground cave, where Dusk and Sylph discover a nest of an unidentified meat-eating Saurian, along with a clutch of mostly unhatched eggs and the rotting carcasses of the parents.
Carnassial, meanwhile, discovers the cave but needs the Hyaenodons to find a larger entrance for him. He schemes with his mate, Panthera; they will destroy all but two eggs, and allow them to hatch. This way, he will be able to manipulate the Hyaenodons by using fear of the Saurians to keep them under his control.
Sylph and Dusk debate over whether to destroy the eggs. However, before Sylph can destroy any of them Carnassial and Panthera arrive and attack. However, before the Felids can kill them, a young Saurian (having hatched prior to the cave's discovery and grown large on the meat of its parents) appears and kills Panthera. Dusk and Sylph escape when Carnassial attacks the Saurian in desperation to help his mate. The Saurian follows Dusk and Sylph out of the cave, where it encounters the Hyaenodons outside and attacks them.
Eventually, Dusk leads the Chiropters to their new home, and the book ends with him leaving the colony to stay with the bats.
In Darkwing, animal species are often referred by their taxonomic clade name rather than their own, which makes it difficult to know exactly what species each creature is. Where the species name is not known, they are listed under the name that they had in the book. The creatures are listed in the order of their appearance. The chiropters are fictional; a hypothetical species intended to represent a primitive bat.