New friends? Or old friends?

G Callen along with his team were once again after some arms dealer. What none of them were expecting though, is the fact that another team is already on this specific case as well.
So what will happen when those teams crash into one another?
Will they work together or is the arms dealer coming lose from all of them?

Callen has called Gibbs for support since he was feeling kind of weird. Will anyone see that those two are way more than just friends and colleagues? Or can those two keep their relationship a secret?
And how will Callen react when someone from Gibbs past suddenly appears?