|Service of:||Laufer (Co-leader)|
|Relationships:||Rosalee Calvert, ex-girlfriend|
|TV Show:||"Cat and Mouse"|
Harmon possesses an extensive knowledge of the history of the Wesen world, demonstrated when he explains to Nick a bit about his resistance group and why they stand in the way of the tyrannical group known as the Verrat.
Ian Harmon is seen walking through Washington DC, when he suddenly stops and hides behind a column, woging in the process. He runs away, and it is seen that a Hundjäger is stalking him. Later, in St. Louis, he is hiding in a hotel room, when he suddenly hears a noise and hides outside the window. The Hundjäger from New York is there, who he disarms and kills. He then escapes before Edgar Waltz enters.
He flees to Portland by bus, using a fake ID that said "Lester Cullum". After being followed there and shot by Waltz, Harmon runs to the tea shop, now operated by his ex-girlfriend Rosalee but was previously operated by the now deceased brother Freddy. As Rosalee works to clean the wound, the Blutbad Monroe appears and while interrogating the veracity of Harmon's story it is revealed that the two had been involved with one another years ago.
He later insisted that he had to leave, on the grounds that merely being with him is enough to put both Rosalee's and Monroe's lives in danger, only for Monroe to inform him that they know someone who can help. Rosalee tells him of the Grimm, Nick. Ian was skeptical, but Monroe pressed on saying that Nick only hunts down Wesen who are a threat to society and even went out of his way to help Rosalee after her brother's death. Ian initially thought that this Grimm they talked about took bribes in exchange for service, until Monroe pointed out that this was not the case, for Nick was a cop. A homicide detective at that. Ian relents and finally agrees to accept assistance from Nick.
When Nick arrives he initially tries to arrest Ian for the murder of Quin, but Monroe and Rosalee alibi Ian. Nick then agrees to help Ian by catching the real murderer: Edgar Waltz.
Ian then goes home with Monroe, to recover.
When Waltz threatens to kill Rosalee, Monroe, Nick and Ian return to the tea shop where the three of them disarm Waltz. Ian then kills him to protect Monroe and Rosalee. Nick apparently arrests Ian, but, drops him off near the bus station with the money and false passport. Nick explained that he was also protecting his friends. As Nick drives off Ian looks after him in amazement.