Hayate the Combat Butler, Vol. 47 (manga)

Having braved snowbound mountains and untamed jungles, Hayate, Nagi, and their surviving classmates enter the wildest arena yet: Las Vegas! There, they face tests of luck and money, the two things Hayate never has. Elsewhere, the quest for the Royal Power heats up, even though no one involved seems 100 percent clear on what it is except maybe Athena? Athena usually knows the score.