Like "Silent Running" and "Take the Reins" on the same album, "A Call to Arms" is a song of rebellion, of the future needing to step up to address the wrongs of the past.
The Arthurian imagery may be literal, or a post apocalyptic dark age, with the "fiery rain" reference making the latter more likely.
A call to rebellion has come, and the downtrodden will rise up.
The children, sheltered with lies, must now be told the truth, and the village leader must step forward in a way he never wished for.
A 'simple man of simple thoughts', he must fill his head with fire--embrace courage, stand fast, and be a beacon to the rest.
The 'torch is lit again'.
The price will be high.
'Sweet Avalon, the heat is on' invokes the serenity and safety of a world now lost, as the lead singer enjoins "run for your life."
War has come.
Hate and oppression has made it inevitable, and the only prayer is that, for the survivors, it will end.
The final chorus is changed; that war is over, but the threat is never gone, that 'simple men with simple thoughts will turn to force as a last recourse."
This is a song that mourns the necessity of war even as it affirms that some battles must be fought, that truth must survive.
It was very pertinent in 1985, and unfortunately is just as timely today.