In 1960, the old hometown of Shun and Ruriko was taken by a construction company. At the old Ukiya Family Residence, Shun asked Ruriko when they would be moving. Ruriko said next week. Ruriko was trying to say something when Kazuko (Shun's mother) called Shun. Shun handed the toy he was holding to Ruriko. Before Shun left, Ruriko confessed she always liked him. Ruriko blushed and waited for Shun's reply. Shun looked away and said he liked Miyu-chan better because she was not a sniveler like "Rurippe". Ruriko just snuffled and could not accept Shun's rude answer. Ruriko sniffed the mucus back and fell to her knees. The ground started to break and Ruriko screamed. <End dream>
Ruriko finally woke up -- and sniveling. The first thing she saw was the toy Shun gave years ago. The toy was a wooden monster and it was displayed at Ruriko's desk. Ruriko snapped and asked why Shun had to be a Gate Keeper. (Episode Title)

Mr. Ikusawa was reading newspaper and remarked that next year's Expo would be good because it would keep the economy booming. Ruriko came down and greeted her parents good morning. Mr. Ikusawa noticed Ruriko was pale and asked if something was wrong. Ruriko said she was fine as she sat on the dining chair. Mrs. Ikusawa remarked that Ruriko was always busy. Before Ruriko could eat her breakfast, she looked at her watch and stood up to go off. Mrs. Ikusawa said it was too early. Ruriko said she was asked to show a new student around the school. Ruriko said her goodbye and went off.

Shun finished his breakfast and told his mother he would be late because he would be coming to a nearby school. Saemi did not approve of Shun's reason because he promised they would go to Shinjuku. Shun promised he would come and then went off.

Shirei was driving a sleek car (Citroen DS Pallas) with Ruriko and Shun. Shun could not wait to see the base of "Earth Defense Army". Ruriko corrected Shun that it was "Eath Defense Organization. Shirei stopped the car in a gas station. The gas station employer asked if Shirei wanted Blend or Regular. Shirei showed a transparent card with an AEGIS Logo in it and said he wanted Special. The gas station employer saluted and began to operate the underground passage.

While being transported underground, Shirei explained that Invaders appeared in 1945 when the World War II was ending. Invaders blended with humans and began creating disputes in Japan. Shun was not really listening but was observing the base. Shun was amazed to see YS aircraft and a rocket underground. They got out of the car and stood along a moving transporter. Shirei continued to explain about AEGIS' function to prevent Invaders from creating further disputes. Shun was still not listening and was commenting that the base was incomparable.

Finally they arrived in a large room. The wide screen began to show a world map. Shun ran to one of the surrounding computers and asked if it was using artificial intelligence. Ruriko called Shun's attention. Shirei continued to explain that AEGIS needs a Gate Keeper who could match the Invaders. Shirei pointed dramatically to Shun and said AEGIS wanted him to be a part of the Gate Keepers party. Shun frowned a bit.

Ruriko and Shun were in an elevator. Ruriko was surprised Shun had to think about joining the Gate Keepers. Ruriko thought Shun would just agree. The elevator stopped at a Science Laboratory. Ruriko reminded Shun to stop calling her Rurippe and said she was different from who she was before. Shun noticed laboratory tools around and wondered if they were in a school. Ruriko explained that AEGIS Far East Branch's Headquarters was located just below the school. Ruriko met up with her classmates who complained about an uprising in their meeting (the girls were Isogai, Aya, and Takanashi and take note they *hated* uprisings). Ruriko told them she would talk to them and advised them to be careful so that other class represantatives would not be drawn into the uprising. When the girls went off, Ruriko asked Shun if he understood that she was different from who she was before. Shun agreed but remarked that she was trying too hard. Ruriko had a disappointed face.

Shun had to go because he had something to do. Ruriko asked if he would join the Gate Keepers party. Shun could not think of an answer yet and he asked if he needed to transfer to Tategami High School (the name of the school) in case. Ruriko said transportation would not be a problem because school dormitories were near. Even though Shun's house was not very far from the school, nearer dorm had an advantage in case of AEGIS call-ups. Shun arrogantly said that earth defense was fun but... Ruriko cut in and said that there was nothing fun about earth defense. They began to argue about the happening last day. Ruriko said it was just luck that Shun defeated the enemy. Shun teased that she was just upset he did her job. A nerd girl walked between them. Ruriko called the girl Kurogane-san. Kurogane remarked that their argument was lover's quarrel. Ruriko ignored her classmate's remark and told Shun to finish their argument. But Shun managed to escape while Kurogane was passing by.

Shun arrived home and saw a note. The note had a doodle of Shun's face and the characters were translated as "My brother is an idiot". Shun took the note and realized he was late for his promise. Shun remembered saying the same phrase to his father.
<Flashback>//His father promised him something but he did not keep it. Shun called his father a liar and an idiot.//<end Flashback>
Shun thought if he did the same thing as his father.

Saemi and Kazuko were watching a youth antiwar demonstration concert. A grownup stopped the youth demonstrators and took the guitar. The grownup played the guitar rowdily and sang, "war is cool, peace sucks". Strange sound wave was suddenly heard. The grownup started to become weird, more grownups followed and started to walk like zombies. A red Invader appeared and initiated the mission. The zombie grownups wore sunglasses and began to transform into black Invaders. The Invaders rose to the ceiling, literally penetrating it. The celing began to shatter, and so did the whole structure. An AEGIS Agent near the place detected the alien frequency and immediately reported it to the headquarters.

Miss Ochiai reported the alien frequency location to Shirei. The Invaders were in West Entrance of Shinjuku station. Miss Ochiai said there was an antiwar folksong going on when the Invaders attacked. Shirei realized that the Invaders were targeting the youth who would shoulder the future. Shirei demanded that Ruriko be dispatched to Shinjuku immediately.

Ruriko was aboard AEGIS bus, headed to Shinjuku.

Shun looked at the chalk drawing on the wall. It was a drawing of a man and a car with the words "My dad is an idiot". Shun opened the door of his father's garage. He came inside and saw a broken paperplane.

<Flashback>Shun's paperplane got broken and his father promised to fix it. Shun became happy when his father said it because he would be testing the paperplane with his friends.

The next day, Shun's plane was not fixed by his father and he was left alone without a plane while his friends played happily. Shun's father apologized and said he did not have the time. Shun was crying while his father was fixing an engine. That was the time he started scribbling "My dad is an idiot" on the wall.

Shun's father begged Shun to forgive him and promised he would come to his graduation because his engine was already finished.

In 1963, graduation of elementary students of Youga East School, Shun waited for his father's appearance. His father promised to come with the car he designed and even promised a test drive after the graduation ceremony. But his father failed to come because of a car accident. <End Flashback>

Shun continued to stare at the broken paperplane.

Meanwhile, Ruriko had arrived in the now wrecked Shinjuku. When Ruriko heard a sound, Ruriko rushed and debris started to fall. Faint voices called out from a blocked rock wall. Ruriko stopped by a rock wall and asked if they were alright. The trapped people replied that there were injured people. Ruriko told them to hold on and promised to get some help. Luckily, Saemi and Kazuko who were also trapped did not get injured. Kazuko assured Saemi that they would be fine because help would come.

The Invaders appeared in the form of an Driller. The Driller disturbed the surroundings, causing more wreckage. Ruriko attempted to attack the Driller but the drill was spinning so fast, the wind pressure formed deflected Ruriko's arrow.

Shun closed the garage door. Shun looked at the sparkplug he got from the garage and said he could not leave his family because he did not want to be like his father. Shun put the sparkplug in his pocket and moved on. Shun saw Mr. Matsuda with his brand new car. Mr. Matsuda invited Shun for a ride. The radio news reported about explosion in Shinjuku. Shun was alarmed when he heard Shinjuku.

Saemi was holding tightly to her mother. The Driller was parrying every arrow Ruriko threw out. Ruriko ran away from the trapped people and continued to attack the Driller. The Driller turned to Ruriko. Ruriko tripped from a rock and her arrows fell out from its dispenser. Ruriko assured herself she could do it then released an arrow to the Driller. Ruriko had three more arrows left. Ruriko ejected two arrows consecutively but only hurt the Driller a bit. Holding the last arrow in her hand she said she was not Rurippe the sniveler anymore.

Mr. Matsuda could not make his car faster because it was brand new. Driven by the need to save his family, Shun opened a huge gate in front of the car. When Mr. Matsuda's car passed through the gate, and the car zoomed wildly. Mr. Matsuda was frightened and he had no control of the car.

A Scouting helicopter reported about the zooming car to Shirei. Shirei must have known it was Shun so he ordered all traffic lights to be turned to green.

The Driller headed to Ruriko. Ruriko was about to eject her last arrow, but the Driller detected another energy source and it stopped. Shun finally arrived at the wreckage and started to call out for his sister and mother. Shun heard Saemi's voice and started to run to it. Debris fell over Shun when the Driller headed to him. Shun's power broke the debris and was greatly angered. Shun released an overwhelming power to the whole place. More debris started to fall and Ruriko ran to Shun. Ruriko told Shun to stop but he would not unless the Driller was finished. Ruriko slapped Shun to his senses and told him to use his gate properly or else the trapped people would be killed. Shun realized what he did and said he just did not want to be like his late father. Ruriko scolded him and ran to the Driller. Shun held to his slapped cheek and remembered Saemi's words, "My brother is an idiot!...LIAR!" Shun rose up and said he was not like his father who died breaking promises. Shun took the spark plug from his pocket.

Ruriko released her last arrow and Shun threw the spark plug. The spark plug was faster than Ruriko's arrow and it destroyed the wind pressure of the Driller. Ruriko's arrow finally hit the unshielded Driller. The Driller was finally gone. Ruriko gave a slight smile to Shun.

Rescue team finally came. The rock wall was opened and Shun called his mother and sister. Shun apologized to Saemi for being late. Saemi jumped to his brother and hugged him. Meanwhile, Mr. Matsuda was crying for his wrecked car.

At home, Shun made up his mind and told his mother and sister that he received a scholarship in Tategami so he would not be staying with them for awhile. Saemi did not want his brother to go but Kazuko allowed Shun with his decision. Just outside where Ruriko and Shirei who were waiting for Shun. Shun bade good bye to his family and finally closed the door to his home.