Recaps

After joining the Silver Hand, Arthas led Lordaeron’s forces to aid Quel'Thalas and built ties with Sylvanas and Kael'thas. He later intervened in Stormwind’s crisis and set out with Jaina, leaving them on their way to Northshire Abbey after helping an injured hunter.

• Arthas swore the paladin’s oath, joined the Order of the Silver Hand, and resolved to use his new standing to strengthen Lordaeron against future threats.
• Arthas and Uther led reinforcements to Quel'Thalas, where Sylvanas’s Farstriders faced a vastly larger Amani Troll force.
• Arthas helped Sylvanas repel the trolls, killed Halazzi, and dispelled Sylvanas’s curse before the defenders endured another attack at Farstrider Hold.
• Arthas and Sylvanas grew closer as they discussed her family and Quel'Thalas, while Kael'thas sought Arthas’s help against Silvermoon’s entrenched councilors and the threat to the Sunwell.
• Arthas recognized Katrana Prestor as Onyxia in Stormwind and offered Varian money to settle the Stonemasons’ Guild debt, recruiting Edwin VanCleef as Lordaeron’s chief engineer.
• Jaina told Arthas that Kel'Thuzad had been expelled from Dalaran and was last seen at Southshore, while Arthas recalled intelligence placing him on a ship bound for Northrend.
• Arthas and Jaina traveled without guards to Goldshire, heard reports of local dangers, and chose to spend the night at Northshire Abbey.
• Arthas healed an injured hunter, and Jaina teleported him and the hunter’s father to Northshire Abbey for further care.

Arthas pursued Mal'Ganis to Northrend, claimed Frostmourne, and defeated the Lich King. He ended the arc by putting on the Helm of Domination and taking control of the Scourge.

• Arthas told Jaina he had arranged Orgrim Doomhammer’s escape, while Orgrim learned that Go'el was alive and resolved to find him.
• Arthas investigated the plague near Brill, killed Kel'Thuzad, and then led his forces to the southern camp, where he defeated Mal'Ganis and rescued Sally Whitemane.
• After Jaina left to negotiate with the tauren, Arthas sailed to Northrend to hunt Mal'Ganis and learned from Medivh that the Burning Legion would return.
• Arthas entered the cavern of Frostmourne, took the sword, resisted its curse, and ordered Brann to return to Daggercap Bay with the Secret Council Knights.
• Arthas killed Mal'Ganis with Frostmourne, then freed Anub'arak from the Lich King's control and led his forces toward Icecrown Citadel.
• Arthas fought Ner'zhul at the Frozen Throne, used Holy Light to break through his defenses, and shattered the ice imprisoning him.
• Arthas put on the Helm of Domination and ordered the Scourge to obey him and kill Ner'zhul’s loyalists.