In this excellent final episode, titled Perfidia, Dan (Kevin McKidd) meets someone who claims to be another time traveler on one of his trips. The problem is that Dan has appeared in an insane asylum, putting everything he (Evan) says in doubt. Evan is infatuated with a woman he met in college who doesn't remember him now, years later.
Dan's brother Jack, who now believes Dan time travels is leaning heavy on the professor/scientist who obviously knows what the heck is going on for answers.
Katie's annoying sister taints the show with yet another appearance.
Livia is pretty much dead weight. Again.
Be warned, spoilers follow...
Dan and Livia keep returning to see Evan in the very recent past (this same year) and assume that their mission is to keep him from being killed. He's been traveling over and over again to try to reconnect with the woman he was married to for 20 years after altering time so he never meets her in order to save her life. He's madly in love and has been trying to continually change things so that he can at least see a spark of recognition from her.
When he finally does, he drops dead for no apparent reason immediately afterwards. At least he dies happy...
I'm really glad that the producers saw this coming and were able to end Journeyman with a sense of closure instead of an abrupt, go nowhere episode.
As it turns out Dan started time-traveling almost immediately upon Evan's death, indicating that no new travelers can enter the loop and that the number of people who can do this is limited. Dan also finally meets up with the suddenly ready to talk professor in an elevator, where we learn that he is not behind this. He has merely been studying and following the phenomenon.
He tells Dan that no one is behind his trips - it's actually intrinsic to Dan himself and has been over the years to a very few people. He also shares the dangers of revealing this ability to loved ones for much the same reason that superheroes have secret identities: There are people out there who if they found out about this would stop at no end to get control of it.
In the end, it turns out that certain sedatives can restrict the ability to travel through time. Evan was in the same place and time for many months while sedated. Dan and Katie have a talk about it close to the end of the episode and he decides that despite the strain on his family and marriage it's too important to set aside.
Although Katie wants a normal life, she abides by his decision, and in the final and emotional scene (for both the characters and the fans), she finally gets to see him vanish.
I'm very saddened that this show had to end, but I'm happy that the series ended in a quality way with it's head held high.
R.I.P. Journeyman - We hardly knew you.