Plugg is a pirate fox with silver fur all over his body except his tail which is orange (hence his surname, Firetail). He was hired by the monarchy of Riftgard to take their princess, Kurda, and prince, Bladd, south to Mossflower Woods. Plugg accepted, though he planned to kill them all on his return and take control of Riftgard. However, as the journey went on, he began to develop a liking for Prince Bladd, who had started the journey as a coward but was inspired by the fox to become more bold and behave like the other pirates.
As the Seascab went south, Plugg and Kurda discovered an intense dislike for each other, often arguing and once even coming to drawn weapons on each other. When they arrived on the west coast of Mossflower, Plugg and his crew captured a group of young creatures: Sagaxus, Scarum, and Kroova Wavedog. Plugg, who had respected an educated uncle in his youth, was very impressed by Scarum's educated way of talking; this, combined with the fact that Sagaxus claimed they all had rich parents who would pay ransom, convinced him to spare their lives. The trio eventually were freed by Triss and Shogg, and in the escape Plugg was thrown overboard into the sea.
Vowing revenge, Plugg and Kurda chased the fugitives upriver to Redwall Abbey, which both desired to conquer. During this trip, Kroova and Shogg set a sharpened pole in the river to spear the small boat carrying Plugg, Kurda, and Bladd. The boat sank, but none of the vermin drowned. Plugg's legendary tail was the only casualty, being chopped clean off. This caused the vain Plugg to force two crew members (Grubbage and Scummy) to glue it on his back-side, and follow him wherever he went to make sure it did not fall off, providing some comic relief. However, during a war dance, Plugg became so carried away that he pulled it off again and whirled it round his head like a banner.
After mounting an unsuccessful attack, the two vermin leaders argued and finally came to a duel. Plugg was killed, not by Kurda, but by Zassaliss, Harssacss, and Sesstra. During the battle, before the serpents came upon the scene, Plugg's battle-axe was lodged deep into a tree when he was attacking Kurda. No one could remove it but Sagaxus, who later came across it and took it as his weapon.
- Plugg is, arguably, the nicest vermin leader in the entire series as not once do any of his minions show any plans of mutiny or disfavor to him and he is the only vermin leader who is outright mourned by his crew as they are left completely lost and even compose a poem when he dies.
- He is, also, one of the few vermin leaders who never execute a disfavored crew member over the course of the book.