The Ambush Field is a location in AMC's The Walking Dead. It is a massive field near the Old Mill Road with a tree that has stained glass windows and it is where the Saviors laid a massive ambush for the Militia, leading to a final battle between the two sides.
Using a fake plan relayed to the Militia via Dwight, Negan lures them into the field while he positions his men on a higher position as a firing squad. As the Militia enters the lower portion of the field, Negan and the Saviors catch their attention by whistling before Negan addresses Rick through a bullhorn, taunting his enemy about the ambush and the situation that Rick has led his people into. On Negan's signal, hundreds of Saviors line up and open fire, only to have their weapons explode, killing most of the firing squad and injuring several other Saviors, including Negan.
Although confused by the turn of events, the Militia takes the chance to attack the Saviors, quickly turning the tables on them. Dwight and Gabriel attack Negan who quickly flees. As Jesus ties up a captured Savior, Morgan considers killing another Savior that he takes down with his staff, but he ultimately takes Jesus' advice to non-lethally subdue the man instead. Realizing that Eugene is responsible, Regina and two Saviors attack him, but he is saved by Rosita. Finally, Laura leads the remaining Saviors in surrendering to the Militia. Rick chases Negan to the tree, running out of ammunition for his Colt Python after a couple of shots and engaging in a brutal hand to hand fight instead. Using the memory of Carl, Rick lures Negan in close before slitting his throat with a piece of glass from one of the stained glass windows.
After a moment, Rick calls Siddiq forward to save Negan's life against the protests of a vengefulMaggie. Having the Saviors lower their hands, Rick gives a speech to the gathered survivors, urging them to find a way to live in peace together and drawing their attention to a massive herd stretching across the horizon representing the true threat that they need to face. Everyone begins to leave with Morgan going his separate way to find peace in himself and Eugene confirming that he was responsible for the sabotage of the Saviors' guns, leading to him and Rosita reconciling. As Rick rests beneath the tree with light from the stained glass windows shining on his face. Rick mutters to himself "my mercy prevailed over my wrath" and laughs.
After Negan attempts to get her to allow him to see Lucille, Michonne tells him that the Militia doesn't have his bat and that it's "still out there", implying that the Militia had abandoned the bat in the field after the final battle.
As a walker wanders across the field, Negan spends hours digging around the tree until he finally uncovers Lucille where it has lain buried for a number of years. Negan examines the bat, remembering the events leading up to him acquiring it and becoming the leader of the Saviors. As the walker gets close, Negan uses Lucille to put it down. However, putting the walker down proves to be too much for the old bat and it finally breaks. Negan sinks to his ground in grief before eventually leaving and returning to Leah's Cabin.