Chapter 100: Vacation starts now!
Izuku and Eternatus starts their clash as Izu uses smoke screen to get on the dragon, but Eternatus rise out of the smoke causing Izu to start punching him with Detroit and Texas smashes. Meanwhile, the Yagi kids couldn't stand watching their half brother fight by himself, so they grab swords and shield and rush out to help Izu. Back at the fight, Izu managed to wrap Eternatus with blackwhip until the dragon unleashed dynamax cannon, which Izu dodge before getting on the dragon to control it. Suddenly, Eternatus attacked Izu with cross poison, causing his friends to get up and rush toward him and begged him to stay alive with tears in their eyes. Suddenly, two mysterious creatures appear before one of them use aromatherapy to heal Izu up before confronting Eternatus. The two creatures then howl before attacking the dragon, causing Rikkido to tell everybody that they should help them defeat Eternatus. The Peanut Gallery then confronts Eternatus with the two mysterious creatures, causing the dragon to transform just in time as the League of Villains woke up from unconsciousness. King M then turn to Eternatus and told him to make him, Gangsta, and Pyscho dynamaxed, causing the drsgon to turn the trio into giants, much to everyone's shock as King M told the Peanut Gallery to meet the darkest day as he uses his scepter to attack one half of the team while Physcho and Gangsta attack the other half. Soon Eternatus began helping the villains, causing Izu to look at the scepter and gets an idea before telling everyone to grab the scepter. After a moment of fighting for the scepter, Shoto destroys it, which caused Mortimer to lose his power just as the Eternatus becomes weak. Izu then noticed a container that keep monster inside before telling Tsu to throw it to him so he can throw it at Eternatus. Soon after a moment of suspense, Eternatus got captured much to the League of Villains shock as King M, Gangsta and Pyscho shrank back to normal. Mortimer then gets an idea and told his comrades to head back to the hideout. Soon when the villains went back inside. The ground starts to shake as the kids witnessed the villains' hideout becomes a giant robot. Izu gets overwhelmed and fell back and landed on a crack with the dynamaxing light, which caused him to become huge, much to his friends' joy and the Yagi kids' shock as they finally reach to see Izu becomes a giant.
Izu got up and told everyone to get somewhere safe because he's about to fight as a giant, which caused everyone including the Yagi kids to evacuate while wishing Labrava join the vacation with them. Soon, the League of Villains began the fight against Izu with missiles, causing Izuku to dodge them quickly before using shoot style moves against the hideout. Izu then uses one for all to blast the hideout into the sea before using a crane's arm to pound the hideout's head, causing an earthquake inside as water starts pouring in. Hammerhead then gets the hideout out of the water before flying back to the battlefield, where it decided to ram itself into Izuku. However, Izu use his strength to push the robot away until his friends and half siblings decided to help him. Izu then allow them before telling them to go inside and shut down the hideout, which caused his friends to go inside and his half siblings to start climbing him. Izu then manage to push the robot away to put his half brothers on his shoulder and his half sisters are on his head before telling them that he'll protect them no matter what. He then continues his fight with the hideout while his friends try to reach the mainframe with Mortimer and Snake on their tail. Mei then captured them in a net before telling Neito to open the mainframe so Siri can put virus inside and make the hideout go haywire. Izuku then smiled mischievously before flying above the hideout to do a super move, causing his friends to come out and yell at him because they thought that he's trying to kill them while inside the hideout. Izu then told his friends to look out as the hideout charged the kids but got punched by Izu. Soon, Izu became weak, causing Sam and Audrey to give him cookies and milk while Tyler gets an idea and gets on top of Izu's head with Nelson before telling the Peanut Gallery his plan. Soon, Izuku gets up as his friends surround him to support him against the League of Villains as the hideout breaks apart because of the virus Siri gives it. Izu then use smokescreen again before punching the hideout multiple times with help of his friends, until it's time for Tyler and Nelson to do a bros. attack with Izu, which is called a drill jump, causing the hideout to become more weaker until it shortened out much to the villains' frustration. Soon, Izu gets an idea when the two mysterious creatures return to help finish the fight before sending out Eternatus. Izu then told everyone to leave everything to him, Eternatus and their new friends, causing the Peanut Gallery and Yagi kids to wish Izu luck as he and the trio of monsters do their super move together, causing the hideout to explode as the League of villains flew up in the air before falling into Eternatus' mouth. Suddenly, the Islanders, Celia, and the U.A. League changed back to their normal self, causing the kids to hug their parents as the islanders cheer for them, saying that they save the island.
The next day, Gulliver greets the party before saying that their vacation starts now, which caused a montage of the adults doing fun things together while the Peanut Gallery and the Yagi kids finally go through the list before ending it with a slumber party outside the castle because Izuku is still a giant. They then have some fun with Eternatus, who is now on their side before having a feast together at the village. The montage then ends in the evening as the kids and Eternatus watch the sunset together until a bot might finally came with the antidote to get Izu back to normal before saying that it wasn't easy to make. After Izu is back to normal, Eternatus gives him a joy ride around the island as everybody follow them as they laugh.