A really cool plot twist might be that the power of the Guardians' friendship and the Avengers' teamwork combine in an unexpected way. Say, when they all hold hands (yes, it sounds a bit cheesy but bear with me), they create a new super - power that can defeat a powerful new villain who is immune to their individual powers. It would show that their unity is more powerful than they ever thought.
One exciting plot twist could be that the Infinity Stones have a different origin in this fanfic. Maybe they were created by an ancient race that both the Avengers and Guardians have to discover together. This would force them to work closely and share their knowledge.
Perhaps a character from the Avengers, like Hulk, has a secret connection to one of the Guardians' pasts. For example, it could be revealed that Hulk's gamma radiation was part of an experiment by the same entity that once abducted Rocket as a baby. This would create a whole new dynamic between the two groups as they try to figure out what it all means.
Chapter 11 is the strongest chapter-level answer because it starts from After a meeting, Shang Shaojing pinched the bridge of his nose, tired, and... and follows through on Miss Qin, please accompany us to the police station to explain this....
Chapter 714, "I'm Using Voice Input", is the clearest early answer because it turns Shen Lan's situation into a concrete plot event. The chapter turns that into something concrete by moving from Jiang Li looked at Jiang Mingyu, who appeared deeply hurt, and...
Chapter 739, "Not Paying Debts, Shameless!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from Shu Yan isn't that ill, it's just a common cold, no, no need to go to...
Chapter 719, "Borrowing Their Luck", is the clearest early answer because it turns Chang Rong's situation into a concrete plot event. The chapter turns that into something concrete by moving from Chang Rong: "Hmph, it has nothing to do with me anyway, since no one...
Chapter 443, "Did Jiang Li Steal Team F's Home?", is the clearest early answer because it turns Team's situation into a concrete plot event. It opens with Team D's captain, curious, turned around and was surprised to find...
Chapter 860, "Is your friend feeling unwell?", is the clearest early answer because it turns Fairy Sister's situation into a concrete plot event.
Chapter 544, "I Shouldn't Have Stopped You from Pursuing Shang Shaojing Back Then", is the clearest early answer because it turns Su Yinwan's situation into a concrete plot event. Early on, [Hahaha, I'm laughing my head off, how come I never knew Miss Zhuola....
Chapter 626, "Emergency PR!", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event. A useful checkpoint is the way the scene starts with The drone hovering in mid-air had precisely captured this scene, and...
Chapter 463, "Even if it's a Wild Boar, I'm Willing!", is the clearest early answer because it turns Dragon Ridge Island's situation into a concrete plot event. Early on, The evening glow gradually bathed Dragon Ridge Island in a dazzling.... By the end, [What??] [Looking for a wild boar??.
Chapter 631, "It's Him Who Got Hurt, Then It's Fine", is the clearest early answer because it turns Hurt's situation into a concrete plot event.