It is a normal day behind Wall Rose, the citizens walking around buying some supplies or ingredients. They are chatting happily, a peaceful day indeed. But suddenly, the ground started to shake and there is a ray of light at the outside of the walls. The citizens covered their heads, protecting their children as the tremor keeps going on and on. After a while, the tremor stopped and the light is gone. Everyone is puzzled and they hope the Scouting Region would investigate that light.

Meanwhile, before the tremor and the mystery light happened, Eren and Lieutenant Rivaille are at the Scouting Region headquarters. They're tidying up the place as the place got rather dusty and the Lieutenant always strict about cleaning as always. "Hey, Eren! You missed a spot, quit daydreaming and do your work properly. I already cleaned the attic and now I'm going to clean outside. I want to see everything here is sparkling clean, got it?!" Said Rivaille and he walked outside. "Y-yes, Sir!" Said Eren and he quickly mopped the floor very hard and cleaning the windows.

While Eren is busy cleaning the dining room, everything started to shake. Some of vases fall and broke into pieces. Eren cannot maintain his balance anymore and he fall on his back. "W-What's going on here?! An earthquake?!" He said to himself. Rivaille slowly walked in to check on Eren. "Hey, are you still alive?" He asked and Eren nodded. Rivaille holding a wooden pole so that he doesn't fall then looked up and wondered, "What in the world is going on?". Before he could think anything else, the tremor stopped and they both looked confused.

They walked out of the building and then, Armin and Mikasa arrived. They came using the horses. "Mikasa, Armin! Did you guys feel that?" Eren asked them and they nodded. "But that was not the only thing that happened. The citizens at the streets said that they saw a ray of light outside of the walls." Said Mikasa. "And we are ordered to investigate so we come here to get you guys because Commander Erwin wants us to meet him at the gate." Armin continued.

Rivaille already ride one of the horses at the stable, he bring another one for Eren. "Well? What are we waiting for? Let's go!" Said Rivaille and he already sprinted to the town with his horse. "Yes, Sir!" Said the three of them and Eren quickly get on his horse before the three of them follow Rivaille. They reached the gate and the whole squad is already there, they all look at Lieutenant Rivaille and the others' arrival. Commander Erwin looked at them and smiled.

"What happened just now?" Rivaille asked with his usual serious expression. Everyone looked at Commander Erwin and wanted to know the answer of Rivaille's question. They all have been wondering since the tremor and the mystery light happened. "It's better if you all see for yourself." Commander Erwin said and he gets on the contraption that lets them go to the top of the wall. The rest of the squad followed him and they all get on top of the wall.

As they reached at the top of the wall, they have surprised expressions on everyone's faces. Eren's eyes widen as he looked where the others looked which is outside of the walls. "W-what are those things?! Where do they come from?!" He asked. Commander Erwin stood next to him and folded his arms. "We don't know but they appeared right after that tremor and that mysterious light" He said. "T-they looked like giant lizards!" Said Sasha and she ate a potato to calm herself down.

What they see outside of the walls is what we call, dinosaurs. Some of them are eating and getting chase by small 3-5 meters class titans. A lot of Velociraptors running around in groups and eat some titans while the medium 10-15 class titans are trying to eat the Brachiosaurus and the Stegosaurus. A lot of smaller titans are wiped out by the king of the dinosaurs itself, the Tyrannosaurus Rex. It roared loudly as it eat the titans' meat.

There are a lot of dinosaurs from different species such as the Pterodactyl, Stegosaurus, Brachiosaurus, Velociraptors, Tyrannosaurus Rex and many more. All rampaging and going towards the walls. "There are different shapes and sizes! What are they?" Eren asked himself. Hanji walked towards them, her hands behind her back and she looked at the dinosaurs. "Those creatures are what we called 'Dinosaurs' They once ruled the world before we and the titans did" She said. "Dinosaurs?!" Everyone surprised and looked at Hanji.

"I'm guessing they eat humans too just like the titans?" Rivaille asked and Hanji nodded. Rivaille sighed and looked at Commander Erwin. "So, what should do to counterattack them?" He asked him. "I'm thinking of sending a few troops there and measure their strength. Do you think you can fight them, Eren?" Commander Erwin asked him and looks at him. Eren looked him and back to the dinosaurs. "I don't know but I'll try my best, Commander!" He said with all his might and he clenched his fist.

Commander Erwin smirked and ordered some of the troops to get some 3D maneuver gear for Eren and Rivaille. They quickly get the gear for them and give it to them. Eren and Rivaille are set while Sasha and Connie stay with Commander Erwin and the rest of the squad so that they can help reloading the cannons. "We'll cover you guys from here, be at most caution. Do you understand?!" Commander Erwin said to Eren, Mikasa, Armin, Rivaille and the other troops. They salute at him "Yes, Sir!" they said before they go to the other side of the walls with their horses.

"Try to get some alive, will ya?!" Said Hanji and she waved at them when they leave the walls. "Should we, Lieutenant Rivaille?" Armins asked him. Rivaille just what is look in front of him. "No. Ignore that crazy idiot" He said and he charged off to the front lines. Armins just laugh nervously and he and the others followed Rivaille. "Try to cut the when you get close to them! We can know how hard their skin by doing that!" Said Armin. The others nodded and tried to cut the Velociraptors. They manage to cut them but more of them keep chasing them with their intense speed.

"Man, this guys are almost as fast as our horses!" Said one of the troops. "But it seems their weakness is either by cutting their throat or just stabbing their heads!" Said the other troop. Suddenly, without they noticing, a giant Brachiosaurus foot just appeared out of nowhere. Its foot just stomped next to the horses and they manage to avoid it. They went under it and looked at its huge body. "Wow, it's huge!" Said Armin. "I could make a joke of what you just said but now is not a good time!" Said Reiner and he passed Armin and ride next to Krista. "T-they looked so scary, Ymir…" Said Krista and she keep closing her eyes when a dinosaur is near or coming at her. "Stop being a wimp, will ya, Krista?!" Ymir said angrily while trying to protect Krista by slashing her machete against two Velociraptors.

They went to the ruins of destroyed village house and hides there for a few minutes. While they are hiding and have a good rest, they watch as two T-Rexes trying to eat and fight a Triceratops. In the end it was an obvious result. The Triceratops got eaten and the T-Rexes are enjoying their meal. Then some of the little class titans joined in and eats the Triceratops meat.

The T-Rexes are angry because they are stealing their meal and the titans got stomped and eaten by them. They sniff in the air as they caught some human scent. They walked towards the ruins, looking for Rivaille's squad. "This is bad, they're getting closer and closer!" Said one of the troops. "Lieutenant! I'll turn into a titan and fight them!" Said Eren. The others looked at Rivalle and waiting for his answer. "No. We can't risk of you changing into a titan yet." He said.

"W-why not, Lieutenant?!" Eren asked him because he was shocked of Rivaille's answer and hope that he could give a good reason. "We're in enemy territory. If you turned into a titan and fight them, the titans would swarm at you and eat you to little pieces. For now just shut up" He said as his face is close to Eren. Eren look down and Rivaille walked to the others. "We'll use this place as our advantage. They are way more stupid than the titans but you can't be more careful" He said. The other salutes at him before they take their positions to launch their attack on the two T-Rex.

"Attack!" They all jumped out of the building and towards the T-Rexes. Will they able to defeat them and solve the mystery of the dinosaurs' arrival? Will they able to solve the mystery and prevent the world from being far worse than it already did? Find out in the next chapter!