During the final shot of the episode, when Mannix is walking along the road with Peggy and Toby and small boy can be sitting on the left side on the road behind the bushes seemingly totally oblivious to the activity around him.
Mark: Because you're going to walk out that door and you're going to find it's all up to you, that you're the only one who can stop me. If you can, of course and you know something else Joe ? You're going to want to do it. Because underneath, you're a killer, too
This is the second episode that Lt. Deegan is in.
This the first episode of the fourth season, with the opening scene that appears the Mannix title, in yellow color.
The introductory scene of Mannix office, during the title of the episode
A ticket to the eclipse, it's the same footage is used in the final scenes of the Season 4
episode 8, The World Between.