The premise of this series is that a group of mercenaries, known as the Damned and led by Captain Gideon, failed in their duty to protect a caravan. They did die gallantly attempting to rescue the survivors. and the Lord and Lady of the River offered them a chance at salvation. They would live in a sort of sleep for centuries in the depths of the river. Those who knew the proper spell, to be recited on the spring solstice, could request them as champions in a just cause. If the gods approved, they would be released to serve the supplicant. They had until the summer equinox to succeed, or they, and the supplicant, would be damned until the end of time.
The five, Gideon, Kane, Murdoch, Averel and Duncan are aided by animal avatars that rest as painting on their shields until released by the proper spell. They have supernatural powers of healing, and do not age.
In the series, they are summoned by Merewan, who is oppressed, along with her people at her estate, but her guardian uncle. What she does not realize is that there is a more serious magical evil threatening the entire country.