The new season of "NCIS" will find Agent Jethro Gibbs (Mark Harmon) battling to overcome a severe case of depression.

Season 13 picks up right where the last one left off, with Gibbs struggling to survive at least two gunshot wounds he suffered in the line of duty, one of them perilously in the chest. As he starts to physically heal and recuperate, emotions start to get the better of the longtime agent and he is consumed with such thoughts as what would become of his family if he were to die.

"He's shot in the chest, he has his knee replaced," show-runner Gary Glasberg told TV Fanatic. "It's an eye opener for him because the Gibbs character literally has to step back and say 'how many more lives does this cat have?' How much more can he live through and if he isn't around to take care of his family, then what happens to his family?"

Glasberg went on to rave about how Harmon is really sinking his teeth into the new plot-lines chronicling all his life changes.

"You're going to see a physical change and an emotional change and Mark Harmon is really diving into that and making it unique. It's been exciting to watch and we've got some really emotional stuff coming up from him."

Initially, one of the people Gibbs turns to for support in battling all his issues is trusted protege Special Agent Anthony DiNozzo (Michael Weatherly), but in time and as all the pressures mount the strain of it all starts to impact their relationship.

"Gibbs and Tony are really going to feel some tension between the two of them," said Glasberg. "Gibbs is putting tremendous pressure on Tony. Having survived this, Gibbs really wants to know if this is what Tony wants. Does he want to be the leader? Does he want to be, in essence, to become Gibbs?"

Popular character Agent Ziva David (Cote de Pablo) is also slated to return to the cast this season. She recently told TVLine, "I think the fact that they never killed the character off is very telling. Under the right circumstances, I think it could definitely be explored."