This multi-player scenario has the same objective as level 13 from the single player campaign. But now you can play it with 4 players online.
Just like the single player level you have to get the Osiris cart to your flagspot. Each player has his own flagspot. Altough you still have to build up a base which was'nt necesary in the single player campaign. The cart is located in the middle and protected by cliffs and bandit migdols so the cart can not be reached until the classical age.
When you have brought the cart to you're spot you have actually already won but the game is not over yet. Because the god Osiris is now under you're control and with him you can destroy you're opponents base in only a few seconds.
For more info consult the readthis.txt which is included in the otow.zip