The novel is set in the world as cats see it, with Man being a mysterious and distrusted creature in the eyes of feralcats. The cats see themselves as the first and most important species. Their myths view humans, or "M'an" as a race of deformed descendants of cats. The novel takes the approach that all creatures consider their kind to be the dominant species of the planet. The book makes reference to mythologies of frogs, foxes and ravens as well as cats.
Fritti Tailchaser, a young ginger tom cat, sets out to stray from his home and clan, the Meeting Wall Clan, in search of his catfriend Hushpad after strange disappearances of the Folk have been reported. The kitten Pouncequick follows him, and eventually catches up. Together, they set out on a long journey to visit the feline royal Court of Harar, with the intention of finding out the mystery of the disappearances. They meet a rather crazy cat named Eatbugs, who travels with them for parts of the journey to the court. Soon they run into some Firstwalkers, cats who live in the wild, who are of a direct bloodline from Goldeneye and Skydancer. Their Thane (leader), Quiverclaw, fights with Tailchaser, but it is more a ceremonial fight and there are no disagreements. Soon, they must part ways. They make their way to Firsthome and the Court, but are treated there with relative indifference. They pick up a new friend, Roofshadow, and go northwest. They are captured by a group of evil cats called the Clawguard, and taken to Vastnir, an enormous mound far to the north, where the evil Grizraz Hearteater enslaves cats to take over the world. Tailchaser needs to alert Prince Fencewalker and Thane Quiverclaw about his evil doings. Soon, Roofshadow creates a hole from above ground, and Tailchaser manages to escape, and races to Ratelaf Forest, where he asks the Rikchikchik (squirrels) to alert them for him. He feels guilty with Pouncequick, Eatbugs, and Roofshadow trapped in Vastnir because of him. He returns to the dreadful mound, where, thankfully, the Thane and Fencewalker come to the rescue. Lord Hearteater (they call him the Fat One) unleashes the Fikos, a dog-like monster of terrible power. Tailchaser takes advantage of the chaos to rescue Pouncequick, Eatbugs, and Roofshadow. They go through the havoc of Vastnir, and lose Eatbugs, the mad cat, on the way. Roofshadow and Pouncequick escape while Tailchaser goes back to find Eatbugs. He goes into a crevice and sees Eatbugs an a near-deathlike state, and feels dazed and confused. Upon uttering a prayer to Lord Tangaloor Firefoot, one of the firstborn cats, Eatbugs awakens, revealing himself to actually be Firefoot incognito. Tailchaser runs out of Vastnir at Firefoot's urging, and meets his friends, while Firefoot goes to deal with Hearteater. After healing, Pouncequick decides to return to Firsthome, and stay there. Roofshadow wants to accompany him, and thus, Tailchaser is left on his quest. He goes east to Bigwater (Qu'cef) and sneaks into a large nut husk (boat) A man approaches and rows across, taking him to Villa-on-Mar. There he meets Huff-so-Gruff, a Growler (dog), and sneaks in an open window. There, in the room, he finds none other than Hushpad, herself. Hushpad wishes to stay, though, so Tailchaser, too, stays for a time. Gradually, Tailchaser realizes that he is still a feral cat, unable to live with man. He begins to see that being domestic has made Hushpad fat and lazy. Realizing that he does not belong, Tailchaser sets out to return home, to see his Meeting Wall friends, to hunt, to see Pouncequick and Roofshadow once more. The ending may be seen only as the beginning of a longer saga, but, to-date, Tad Williams has yet to revisit his feline homage to Tolkien with additional writings.
The cats of Tailchaser's Song have a well established system of songs, poems, and godly figures, such as Meerclar the Allmother and her Two, Harar Goldeneye and Fela Skydancer, and the three Firstborn cats. The cats, as one brethren, call themselves 'the Folk'. The novel contains a developed system of cat speech and style as well, to go with their customs; very similar to what the reader finds in written editions of the works of J. R. R. Tolkien.
Tad Williams has come up with a very large variety of terms, called the Higher Singing, used by the cats to express themselves and explain things. Included in the book is a complete glossary, as well as a character 'directory' and a map of Tailchaser's world. Also included are Williams' notes on pronunciation, which apply not only to spoken words but to first names as well (such as Fritti, Harar, or Meerclar):
'C' is always pronounced 'S': thus, Meerclar is pronounced 'Mere-slar.' In the instances where an 'S' has been used, it is only to clarify the pronunciation. For example, I felt that 'Vicl,' although the true spelling, was a little boggling; hence, 'Visl'. 'F' has a soft 'fth' sound. Vowels tend to conform to Latinate 'ah-eh-ih-oh-ooh.'
In November 2011, it was announced that Animetropolis is developing a computer-animated film adaptation, with International Digital Artists, the producer of Cat Shit One, animating it.Tailchaser's Song is set to be released in the United States in 2016.