Shadow: ...I shouldn't have made her come.
Chance: It's not your fault, she wanted to come.
Shadow: But it's my responsibility. I had a responsibility to Sassy, to love her and protect her. The same as I have to you... and to Peter. And the same as you have to Jamie.
Chance: But we didn't ask for this job.
Shadow: We didn't have to. It's built in. Has been ever since the dawn of time, when a few wild dogs took it upon themselves to watch over man — to bark when he's in danger, to run and play with him when he's happy, to nuzzle him when he's lonely. That's why they call us man's best friend.