Cao Cao gets Liu Bei and his brothers past the gate into Yuan Shao's alliance, commenting that no one can tell who might become a hero in the future. While this is a clear foreshadowing of Cao Cao and Liu Bei's later conflicts, there's a bonus here; the camera focuses on Guan Yu, the man who would posthumously become the Chinese god of war.
Guan Yu kills Hua Xiong without even breaking a sweat, then marches back into the hall accompanied by victory music and tosses Hua Xiong's head at Yuan Shao's feet — and the wine poured for him before his departure is still warm.
Cao Cao and Liu Bei both give What the Hell, Hero? speeches to Yuan Shao as they leave the alliance, accusing him (and the rest of the alliance) of having been "in it for themselves" and not helping either of them, while Sun Jian just points a sword at his throatnote after Yuan Shao orders hidden troops to seize Sun Jian and confiscate the Imperial Seal.
Sun Quan successfully negotiates with Liu Biao for the return of his father's body and a peace between their respective houses. For full context, Quan is nine years old at this point.
Just as Dong Zhuo seems ready to become Emperor, Wang Yun shows himself at the top of the palace steps, calls for Dong Zhuo's execution, and reveals the coup de grace of his master plan: Lu Bu thundering in on Red Hare with his halberd in hand.
Zhao Yun's debut battle has him basically taking on Cao Cao's Xuzhou-invading army all by himself, to the point that even Cao Cao is impressed. Then when the rest of Liu Bei's army arrives, they force Cao Cao's much larger army to retreat.
When Zhao Yun's feats are repeated at Dangyang on an even greater scale, Cao Cao orders that his troops are not to use arrows but instead take Zhao Yun alive, because he's so smitten with Zhao Yun... until Cao Ren points out what happened with Guan Yu.
Lu Bu shows unexpected guile by convincing Liu Bei and Ji Ling, the commander of Yuan Shu's army, to agree to make peacenote or else Lu Bu will war with the offender if he manages to shoot the tassel off his halberd at a hundred steps... then he actually does it.
Zhang Fei: Damn it Lu Bu, you're good!
Yuan Shu asks Sun Ce why he hasn't left for Lujiang yet, as ordered. Sun Ce replies that he's already taken the city, and presents the head of its former commander Lu Kang.
Chen Gong refuses to work for Cao Cao again after Lu Bu's defeat, telling him to hurry up and kill him already or he'd use every talent in his arsenal to make Cao Cao's life hell.
Backed up against the riverbank with Cao Cao's forces bearing down on his ragtag band, Liu Bei turns to face the approaching army, declaring that he will fight until the last and then take his own life. Zhao Yun, Zhang Fei, and the rest of their forces join in swearing that "though we were not born together, we shall die on the same day!"