If our kingdoms should fall

Chapter 1: the letter

My fellow rulers,
I apologise for the lack of formality in the delivery and writing of this letter, but an urgent situation has arisen. Earlier this morning, I recieved word from Infernium that Haelios plans to declare war on Carthion at sunrise on the second Sunday of the month, that leaves me only 10 days to rally my army, when he has had months, even years. I fear my army alone will not be strong enough to hold him off, let alone stop him from infiltrating Carthion and taking my kingdom as his own. It is with the heaviest of hearts that I plead of you, as my allies, to assist me. Haelios is not yet aware that I know of his plan, so we must remain as if we are unaware for the next 10 days, we must not unleash our armies on him yet. I have formulated a plan, should you all choose to help me. Since there is unlikely to be time for me to recieve your responses, and then write a second letter of my own, I will include the plan In this letter.
Each of you tell your most trusted general of the situation, and allow them to prepare your armies for battle on the second Sunday. The three of you are then able to discreetly make your way to Carthion, to join me and my army, as I know you are all skilled warriors and I believe your help in the battle to be vital. On the tenth day, when Haelios strikes, your armies will be ready and waiting for the order to be sent marching to the Carthion borders, trapping haelios and his army within its land. Here we may defeat Haelios. It is my wish that we spare as many of his subjects as we are able to, on the condition that they do not continue the war their king started. It is vital that I send this letter, this plea for help, because my Queen, my Thalia, is expecting our first born child. I cannot allow this child to be brought into a defeated kingdom.
Astoria, kind and true, but a warrior stronger than even the highest ranking of soldiers. Theoron, mysterious and fearsome, I know how hard this must be for you, joining a battle to defeat your brother. Khalisi, strong and brave, your leadership and intelligence is to be admired and valued in this battle.
I believe with the four of us and our armies we may be able to defeat the kingdom of Infernium, if you begin your journey now, I believe you will be able to reach me within a week. Needless to say travelling discreetly is necessary, even if it does add time to your journeys, we must not let Haelios know we are aware of his plan.
I hope to see the four of you within the week.
eternally grateful,
King Ardeus of Carthion