- "I'm sorry for -- for ratting you out. You know, when you and Lydia were hiding in the clubhouse. I-I mean, I didn't want to get you in trouble, but I just caused more trouble."
- —Addy to Henry.[src]
Nothing is known about Addy's life prior to or as the outbreak began.
Although unseen, Adeline was living in the Hilltop Colony during the events of the war.
At night, Henry drinks with his new friends in a shed outside of Hilltop. Gage suggests they have some more fun and takes them to a covered hole in the ground with a walker inside. However, Addy leaves as they throw rope rings at it and Rodney pees on it.
In Hilltop, as the residents search the town for Henry and Lydia, who have gone missing, Adeline approaches Enid and informs her that she thinks she knows where Henry ran off to. She and Enid sneak out the back of Hilltop to avoid detection by the Whisperers.
In the woods, Adeline and Enid find Henry and Lydia at the Hilltop teens' hideout. She watches on as Enid attempts to convince Henry that they must return Lydia to the Whisperers, for the safety of Alden and Luke. After Henry agrees, Adeline returns with Henry, Enid, and Lydia to Hilltop.
At night, Adeline approaches Daryl and gives him a letter left behind by Henry, indicating that he went after Lydia.
On the road, Addy and Tara's group clear a tree from their path to the Kingdom to ensure the roads are cleared for Alden's convoy carrying the food and trade goods for the fair. Upon finding a downed tree, Addy remains alert and checks the surrounding area. She keeps on watch as the others help chop the tree into pieces to clear the road.
Later, a small herd of walkers approaches the group. They get in position and remind themselves to watch for the Whisperers. When Gage is attacked by a walker, Addy rushes in and saves him. Suddenly, the Highwaymen ride up on horses and introduce themselves to Tara after helping to take down the herd. They then escort them to the Kingdom, having accepted Carol's deal.
In the Kingdom, Addy excitedly looks around the Kingdom with Gage and Rodney.
In the Kingdom, Addy watches from the crowd as Ezekiel declares they've finally accomplished Rick, Carl, and Jesus' dreams of reuniting the communities. “Let the fair of a new beginning begin!” Ezekiel says as everyone celebrates and applauds.
In the fair, Addy talks with Henry and apologizes for ratting him out earlier, although he claims they are good. Somehow, Addy is among the residents kidnapped by Alpha and taken away to a stable in the woods.
In the stable, Addy alongside the other tied up residents are about to be attacked by the Whisperers but are found by Ozzy, Alek, and D.J., giving the group a chance to fight back. In the middle of the chaos, Alpha arrives and the group is subdued and then killed, only leaving Siddiq alive as a witness. Later, Alpha puts Addy's decapitated head on one of the several pikes used for the Whisperers' border.
Later, in the Kingdom, Siddiq delivers the tragic news to the crowd, tells them how brave everyone was in their final moments and how they all fought back. He encourages everyone to remember the fallen as brave heroes and to honor them.
- Killed By
- Alpha (Alive, Off-Screen)
In order to mark a border between the land belonging to the Whisperers and the communities, Alpha disguises herself and infiltrates the fair to kidnapp several residents. Afterward, she decapitates them and then places their heads on wooden pikes to mark the border, with Addy being among them.
After finding the border, her zombified head is put down by either Daryl, Carol, Michonne, Siddiq, or Yumiko.
This list shows the victims Adeline has killed:
Addy had a crush on Henry from the moment she saw him in "Stradivarius". She was concerned about him when she saw how down he looked after he discovered that Enid was dating Alden. Despite being close friends to Gage and Rodney, she preferred Henry. When Henry hid Lydia in their clubhouse, Addy reluctantly assisted Enid in finding them. She immediately apologized to him twice for this as she didn't want to betray Henry. As both Addy and Henry were killed off-screen around the same time, it's uncertain who died first, therefore, it's uncertain how either one of them reacted to their deaths. It's possible Addy was horrified at seeing Henry's death, knowing it's coming to her.
- While Adeline was not introduced until Season 9, her character was present for all of All Out War. Furthermore, she has been at Hilltop from seemingly its inception as she states that she's lived there for almost half her life.