After the Fell Dragon Grima's defeat at the hands of Robin and Chrom, the shephards can finally live in peace. However, Robin decided to leave the team in order to train, should the Fell Dragon return. A year has passed since Robin's departure and the lands is still peaceful. At the castle balcony, Chrom can be seen there, looking at the view, until Lissa comes in and talks to him.
"Are you sure Robin's gonna be fine on his own?" Lissa asked.
"Yes, I'm sure of it. It's best if we let him do his own thing..." Chrom responded.
"What about Lucina?" Lissa asked again.
"She'll be fine, as well. I believe that she can change the future." Chrom answered.
"I sure hope so..." Lissa said.
"What's wrong, Lissa?" Chrom asked.
"It's been a year since we defeated Grima and I already missed Robin." Lissa answered.
"You're not the only who missed him. All of us do." Chrom said.
"By the way, where was he training?" Lissa asked.
"From what he said to me, he's training in a place far away from Ylisse." Chrom answered.
"I sure hope he's okay there..." Lissa said.
"Don't worry, Lissa. He can handle on his own, I believe in him." Chrom said.
But then, they saw a purple light in a distance. They wondered what it is.
"What was that?" Lissa asked.
"I don't know, but something tells me that it's bad..." Chrom answered.
"Should we go and check it out?" Lissa asked.
"Of course. Let's go!" Chrom said.
"What about Frederick?" Lissa asked.
"He's probably busy at the moment, so we can't bring him." Chrom answered.
Chrom and Lissa then exits the castle and goes to where the light came from. On the way, they encountered Lucina, who has returned from the future to investigate something.
"Father!" Lucina said.
"Lucina? What are you doing here? I thought you retruned to the future." Chrom asked.
"I came back to investigate something. I saw something that was not supposed to be in the future." Lucina responded.
"You think it has something to do with the light that we just saw?" Lissa asked.
"What do you mean?" Lucina asked.
"Well, when we were in the balcony, we saw a purple light somewhere around Ylisse, so we decided to investigate." Chrom explained.
"Then, I'll join you in this investigation. I had a bad feeling about this, Father..." Lucina said.
"Me too. Let's go to where that light is." Chrom said.
The three continued on their way towards the location of the light. When they arrived there, they saw a large army of Risen gathering around the place, led by what seems to be a man wearing armor and a green cape, holding a scepter.
"Risen! I knew there was something odd about that light..." Chrom said.
"But I thought we defeated them all..." Lissa asked.
"Not all of them. It appears that these remnants are up to something." Lucina answered.
"Who is that guy leading them?" Chrom asked.
"I don't know, Father. I've never seen him before..." Lucina answered.
"We should stop them before their plan succeeds." Chrom said.
"I'll help you deal with them, Father." Lucina said.
Chrom and Lucina then charged into the army of Risen and they were easily defeated by the two.
"It looks like that we have an intruder..." The man said.
"Who are you and why are you leading these Risens?" Chrom asked.
"The name's Loki. And yes, I am currently leading these undead army." Loki responded.
"Loki? I've never heard of that name before..." Lucina said.
"Ah, yes. That's because I am not of this world." Loki said.
"What do you mean by that?" Chrom asked.
"You see, I came from another world different from this one." Loki answered.
"How did you end up here?" Lucina asked.
"I'm afraid I'm not going to tell you..." Loki responded.
"Whatever you're planning, we're going to stop it!" Chrom said.
"Oh? Did you really think you stand a chance against a god?" Loki asked.
Chrom and Lucina tried to attack Loki, but he easily defeated the two.
"Are you two okay?" Lissa asked.
"Ugghh...He's too powerful..." Lucina answered.
"Hahahaha! With the army of the undead in my hands, I can finally beat my brother and his so-called Avengers once and for all!" Loki exclaimed.
Loki then used his scepter to open up a portal.
"Where do you think you're going?" Lucina asked.
"I'm not gonna hang around here much longer. I must go back to my world and I'll brought along these undead army with me." Loki answered.
The Risen army then all go through the portal, until Loki was the only one remaining.
"Farewell, warriors from another world..." Loki said.
Loki managed to go through the portal.
"Father, we should give chase!" Lucina said.
"Right." Chrom said.
"What about me?" Lissa asked.
"You should go back to the castle, Lissa. This is a dangerous mission." Chrom answered.
"What should I say to the others if they found out?" Lissa asked.
Lucina saw the portal slowly closing.
"Father! The portal's about to close!" Lucina said.
"There's no time, Lissa. Go!" Chrom said.
Lissa reluctantly runs back to the castle while Chrom and Lucina managed to go through the portal just in time as the portal closes.
In another world...
It's been a year since the Avengers defeated Ultron in Sokovia and since then, the earth is at peace. Tony Stark can be seen in the Avengers Tower, building some kind of armor. Then, he heard a voice, which actually came from his A.I., Friday.
"Are you gonna be fine, sir?" Friday asked.
"What are you talking about?" Tony asked back.
"It's been 2 hours since you start making the armor." Friday responded.
"Don't worry about me, Friday. I'll be fine." Tony said.
"If you say so..." Friday said.
"Oh, by the way, could you call Steve Rogers for me?" Tony asked.
"Will do, sir." Friday responded.
After a few minutes, Steve responded the call.
"Tony?" Steve responded.
"Hey, Steve. How's the New Avengers doing?" Tony asked.
"They're doing just fine, Tony." Steve responded.
"Are you sure about that?" Tony asked.
"Yeah. I've been monitoring their progress and it seems that they're ready." Steve responded.
"Even Rhodey?" Tony asked.
"Yes, even General Rhodes." Steve responded.
"Glad to hear it." Tony said.
"What about you? I haven't heard of you for a year now." Steve asked.
"Well, I'm still here at the Avengers Tower, making a new armor..." Tony responded.
"But I thought you retired. You said it yourself." Steve asked.
"Look, I may be retired, but I'm still a hero, Steve." Tony responded.
"Heh. You make a good point." Steve said.
"By the way, where's Natasha? I thought she was with you." Tony asked.
"Oh, she's in the training room right now." Steve responded.
"I see..." Tony said.
"Well, I better go now. I still had some evaluation to do." Steve said.
"Oh, me too. I'm gonna have to finish this." Tony said.
"It's been nice talking to you, Tony." Steve said.
"You too, Steve." Tony said.
The phone call ended and Tony resumes his work. But then, Friday informed him about something.
"Sir, I've been detecting some kind of portal signature somewhere in New York." Friday informed.
"A portal signature? That can't be good." Tony said.
Tony stops working for his armor and goes outside the lab.
"Alright, bring me the Mark 45 armor." Tony said.
"Will do, sir." Friday said.
Then, some mechanical claws come out and helps Tony suit up with the Mark 45 armor. After a while, Tony is finally suited up.
"Alright, let's roll!" Tony said.
He then flies off from the Avengers Tower.
Meanwhile in New York, a portal appeared and Chrom and Lucina came out of it.
"What the? Where are we?" Chrom asked.
"I am not familiar to this place at all..." Lucina responded.
The two wandered around and they were amazed by the buildings and cars.
"I've never seen such buildings like this before..." Lucina said.
"And those metal wagons as well." Chrom said.
"I have never seen anything like this in our world..." Lucina said.
"Yeah. It's completely different compared to ours..." Chrom said.
"Alright, where did that Loki go?" Lucina asked.
"I don't know. Should we search for him?" Chrom asked.
"It's going to be hard, though. Especially since we're not familiar with this place." Lucina said.
In the sky, Tony, as Iron Man, has arrived to where the portal is.
"Is this the place?" Tony asked.
"Yes. But the portal already closed, sir." Friday responded.
"Damnit!" Tony ranted.
Tony then noticed Chrom and Lucina on the same spot as the portal was.
"Hmm...There's two wearing some kind of a medieval costume..." Tony thought.
"I can confirm that those two came out of the portal. They had the same signature as the portal." Friday informed.
"Well, let's ask them out." Tony said.
Lucina noticed Iron Man landing on their location.
"Father, look!" Lucina said, pointing to Iron Man.
"Is that...a knight?" Chrom asked.
"Maybe, but this knight can fly on it's own..." Lucina responded.
Iron Man approaches the two and asks them.
"Did you two just came out of a portal?" Iron Man asked.
"Yeah. We were looking for someone who came in here." Lucina answered.
"Oh, so you two are not the only ones?" Iron Man asked again.
"Yes. We're looking for someone named Loki..." Chrom said.
The mention of Loki makes Iron Man a little worried.
"Wait, did you just say Loki?" Iron Man asked.
"Yes. Why?" Lucina asked.
"This is bad...If Loki's back, then..." Iron Man thought to himself.
"Is something the matter?" Lucina asked.
"Oh, nothing. It's just...I can't believe he's back." Iron Man said.
"What do you mean?" Chrom asked.
"Let's not explain here. You two better come with me." Iron Man said.
"To where?" Chrom asked.
"Over there." Iron Man answered as he points to the Avengers Tower in the distance.
"Is that a tower?" Lucina asked.
"Yes, it's called the Avengers Tower." Iron Man answered.
"Alright, let's head over there. Lead the way." Chrom said.
Chrom and Lucina followed Iron Man on their way towards the Avengers Tower.
Meanwhile, in Asgard, Thor can be seen talking to Heimdall in the Rainbow Bridge.
"What is it that you want me to talk about, Heimdall?" Thor asked.
"It's about Loki..." Heimdall responded.
"What about him?" Thor asked.
"He has returned." Heimdall answered.
"What? I thought he died on Svartalfheim." Thor was shocked.
"Now, he has brought an undead army from another universe to invade Earth once more..." Heimdall said.
"This can't be good. I must go back to Midgard and informed the Avengers about this..." Thor said.
"Very well." Heimdall said.
He then activates the Rainbow Bridge, allowing Thor to go back to Earth once more.