It's "Hidden", the opening game of the Grand Magic Games, and Gray finds that it's like playing cat and mouse. Unfortunately, he's the "mouse" as he keeps getting picked off by a member of Raven Tail!
s04e01 - Sabertooth
s04e02 - And So We Aim for the Top
s04e03 - Song of the Stars
s04e04 - For All the Time We Missed Each Other
s04e05 - Crocus, the Flower-Blooming Capital
s04e06 - Sky Labyrinth
s04e07 - New Guild
s04e08 - Night of Shooting Stars
s04e09 - Lucy vs. Flare
s04e10 - Portent
s04e11 - Chariots
s04e12 - Elfman vs. Bacchus
s04e13 - Mirajane vs. Jenny
s04e14 - Kagura vs. Yukino
s04e15 - Hatred at Nightfall
s04e16 - Pandemonium
s04e17 - 100 Against 1
s04e18 - Laxus vs. Alexei
s04e19 - Wendy vs. Shelia
s04e20 - Small Fists
s04e21 - Naval Battle
s04e22 - A Parfum For You
s04e23 - Battle of Dragon Slayers!
s04e24 - Four Dragons
s04e25 - Natsu vs. the Twin Dragons
In the land of Fiore, magic is everywhere. Sorcerers are like skilled tradesmen who band together in 'guilds' and take on paying assignments for non-magic wielders, like hunting monsters, retrieving lost items or running odd errands.
Lucy is an aspiring wizard who wants to hook up with the coolest guild around, Fairy Tail. One day, she meets a red-headed boy who saves her from a unscrupulous wizard, and before she knows it, she's introduced to the wild and wacky band of wizards of Fairy Tail and begins the adventure of a lifetime.