Quentyn Martell and friends did indeed join a free company of soldiers, though not the Golden Company. They recently raided Astapor. It was a bloodbath. Now they are heading for Meereen.
The Yunkai are in charge of all this. They don't seem very well organised, but they do have the free companies.
Quentyn and friends need to desert and go and join Dany before the battle starts against her. Luckily they get sent on a secret undercover mission to pretent to go and join Dany. That's pretty convenient!
