Whilst waiting for the Clave's decision on whether to surrender or fight Valentine and his demonic army, the Downworlders arrived at the gates of Alicante to await their decision by sundown. Clary Fray was able to create the Alliance rune, allowing the Shadowhunters and Downworlders to bind together to share each others' fighting skills, speed, strength and agility during a battle.
Simon Lewis was fighting in the battle of Brocelind Plain when he accidentally fell into a ditch, which he later described to Clary as the "worst 10 minutes of my life." However, due to the events that took place near Lake Lyn between Valentine, Jace, Clary and the Angel Raziel, Valentine was killed and the demons vanished.
Unfortunately, there were still many casualties among the Nephilim and Downworlders, despite the battle of Brocelind Plain only lasting minutes.