Instead, it is about those brave and heroic men who fight fires and who rescue people from burning buildings. It is about those alarmingly large  and disturbingly strong-looking men who show up in the lobby of your office building  wearing more equipment than you could lift -- oxygen tanks, boots, hard hat, fireproof pants and jacket, and an axe that seems larger than the average person.
Thus, even if a firefighter piece is a mere Pawn, it can still lift a big heavy Rook or Queen and rescue it.
However, in some benighted nations, firefighters have been used to assail citizens who have exercized their right of peaceful assembly to remonstrate against excesses of the government; usually water cannons rather than hosemen, but this real-world application of the hose is used in Firefighter Chess, where a firefighter piece can squirt a piece away from itself.
It is also thus in Firefighter Chess.
Therefore, in Firefighter Chess, the firemen are hidden pieces.
Each player has one piece or Pawn which, in addition to its ordinary move, is also a Firefighter. However, until the firefighter declares itself, it could be any piece! In other words, you do not have to choose which piece is your Firefighter until you want to make a Firefighter move. This rule is inspired by the Jester.
The Firefighter declares itself by making one of the three possible Firefighting moves: squirting, extinguishing, or rescuing. After declaring itself, a Firefighter retains the ordinary powers of the piece it started as, but also has the powers and the duties of a Firefighter; and of course, if a Firefighter Pawn is promoted it remains a firefighter -- becoming, for example, a Firefighter Queen instead of a Firefighter Pawn.
Squirting can cause a situation where multiple pieces occupy the same square. You may not move any pieces onto a square that contains only friendly pieces. When you capture on a crowded square, all pieces, both friend and foe, are captured.
This sounds like a complicated rule, but it's really very simple. The Firefighter must do its duty, but not at the cost of the game.
Think of the rule in Bridge, where if you expose your 3 of Diamonds you must play it "at your earliest opportunity". Sometimes it restricts your choices and makes you lose, but sometimes no harm is done; and this is the idea behind Firefighting Duty.
Compare with the rule of compulsion in the Game of Nemoroth: compulsion can win the game outright, but Firefighting Duty is not nearly so severe; and in order for the rule to be not so severe, the rule is written so that if any of your pieces are attacked you can ignore the fire.
A piece which is on fire cannot move, and if you are stalemated while you have a piece on fire you lose the game.
Your Firefighter has no duty towards a friendly fiery piece. If this seems arbitrary, consider Crassus.
Your Firefighter can extinguish a friendly fire or rescue a friendly fiery piece.
The arson rule was created as a strategic counterweight to the power of the enemy Firefighter.
1. e4 e5 2. Nf3 Nf6 3. Bc4 Nc6 4. Ng5 Bc5?
The Wilkes-Barre Counter Gambit may not be not a good choice in this game. However, it is a good choice for giving us an example of how the rules work!
This is effectively check because the Nf7 can declare itself to be the White Firefighter by squirting the Ke8 off the board; and that, of course, would be capturing the King and it would end the game.
Because e4 and f2 are attacked by Black, arson would not help at all.
Because both 5...Ke8-f8 and 5...O-O allow the Nf7 to squirt the King off, the only possible normal reply is 5...Ke8-e7, and the Queen is lost. Therefore, Black must in desparation try a defensive squirting!
If 5... Ke8 squirts N from f7 to g6, Black is doomed because White's arson will soon follow and will force the Black King to advance into dangerous territory; this will happen slowly, gradually, and gently, with the unusual characteristic of the play being that the greatest threat and forcing move W can make will be to arrange for none of Black's pieces to be attacked!
If 5...g7 squirts N from f7 to e7, the Ne7 can still squirt the Black King off the board.
Therefore only 5...Nf6 squirts N from f7 to f8 will do the trick, and when I study the position after that I suddenly realize that 5. Ng5xf7 was a bad move!!! The Nf8 is trapped!
Apparently, White should have played 5. Bc4xf7+, which forces Ke8-e7 (squirting the B to f8 allows it to capture c5), but does not lose the Queen! In that case, White would need to retreat the B from f7, just like in FIDE Chess, and the game would be complicated and undecided.
Arson and Extinguishment are logical ideas from the theme of the game.
Rescue is also logical for the theme of the game, but is an unusual new idea which allows some pieces to change their allegiance.
I wrote a whole series of articles about multiple pieces on the same square: Crowd Chess 1, Crowd Chess 2, FIFO Chess and Multiple Occupancy Miscellany.
I wish the rules could be shorter, but I think you will find that the rules are very logical and appropriate to the theme of the game, and that this will make the rules easy to understand and follow.
 Perhaps the axe makes the firefighter seem larger than he is?
 Ten such giants showed up at 75 Wall Street in August 2001 in response to an alarm system problem; it is very likely that most of them died a month later.
 Freud was never a firefighter.
With all due respect to the heroes of the real world, I must have fun with my subject matter for I am a Jester.