Fairy Tail 429 gets into gear as Lucy nearly gets cut in half when Gray shows up to freeze Goumon just before he’s cut in half. It seems that all this was in fact Gray’s mission as Erza and Gray have been in contact all this time trying to infiltrate Avatar in order to crumble it in from the inside.
Fairy Tail 427 see’s Natsu and Gray finally meeting when they invade in the headquarters belonging to Avatar. Natsu, Lucy and Happy all try to quickly jump into action when Lucy tries her best to sneak in without alerting anyone, however Natsu just shouts Gray’s name whilst inside to get his attention.
Fairy Tail 426 see’s plans from Avatar being revealed to the Council when they think Gray is the person leaking it all, when he reveals that his only reason for being there is to find and destroy END. Natsu tells Lucy and Happy about what Future Rogue said, when we also see that Natsu, Lucy and Happy reach the base of Avatar, while Gajeel and Lily, now part of Council, figures that he should try and stop Avatar.