Toaru Kagaku no Railgun Episode 20

Synopsis
Nighttime Academy City is shook by another tremor.

Kongou Mitsuko, who was busy studying, felt the quake from her dormitory room. She shrugged it off as another quake among those happening in the city for a few days that time, but as she reached to pick up her cup of tea, it moved by itself and broke after falling from the desk. It was followed by her entire doll collection floating as if picked up by a ghost.



The next day, at Sakugawa Middle School, Uiharu is called by her homeroom teacher and told her that a newly-transferred student will be her roommate: Haruue Erii.

Later on, Mikoto, Kuroko and Ruiko discuss on the newest transfer student from the 19th District as they went to Uiharu's place, where she and Erii prepare to move the latter's things in the former's room. With Kuroko's help, they moved in the boxes of Erri's belongings in, leaving the Teleporter and the others to organize them inside.

With the work done and with Kuroko and Uiharu needed for a joint meeting between Judgment and Anti-Skill regarding the recent earthquakes, Mikoto and Ruiko decide to tour their new friend around her new home and treated her some crepes. As they ate on the same bench where Ruiko and Uiharu became friends with Kuroko and Mikoto (in Episode 01), Mikoto expresses her disappointment that they were not complete due to the joint meeting the two Judgment members are required to attend. Saten then insists that the earthquakes, according to a rumor, is instead a poltergeist (a supernatural phenomenon).

This is debunked by Yomikawa Aiho, who is one of the speakers for the joint meeting held at the Anti-Skill 7th District Headquarters. According to her, it is a 'simultaneous outbreak of RSPK Syndrome'. (RSPK stands for recurrent spontaneous psychokinesis.) Then, a woman named Therestina from the Multi-Active Rescue Squad (MAR) explains that RSPK occurs when espers lose control over themselves, releasing an immense amount of power. She also adds that RSPK happens in the individual level, and earthquakes like the one happening recently can only happen through a simultaneous manifestation of RSPK.

After the joint meeting, Kuroko and Uiharu meet up with Ruiko, Mikoto and Erii at Playland GAU to play some games (and to persuade Erii to play some as well). They also took a picture of themselves in a photo booth and while resting, Saten remarks that Erii was like Uiharu in the past.

The topic soon shifts to the upcoming Academy City Fireworks Display, where everyone decides to participate in.

Konori frantically talked to Kuroko, finally finding out important information regarding the Poltergeist phenomenon after hours of research. She told her that the phenomenon has a chance of being created by deliberate interference to espers' AIM diffusion fields.

All of a sudden, the platform where the girls are at began to shake and lose integrity. Another earthquake is taking place. Part of the platform gives in to the quake's force, but Kuroko manages to teleport herself and Mikoto to safety. Meanwhile, Saten can barely move due to the earthquake and Uiharu was covering Erii when a light post came crashing down on her. Out of nowhere, a robot-looking machine with dark red and pink markings on it lifted the light post and averted the disaster from happening. Soon, the voice of Therestina emerged from the machine.

With the earthquake subsided, Erii mutters "Where are you?" while clutching her locket.

From a distance, a familiar figure prepares to take off her clothing.

Therestina shows a wide grin.

All of these happening under what seemed like the happiest moment of the summer vacation.

Adapted From
Adapted from? which chapter of manga and/or novel

Referbacks
references to previous episodes, possibly from Index(based on timeline)

[Daigo] has ring because he proposed to the principal of Cypress Park Orphanage.

New Characters
Haruue Erii - introduced in Episode 17 as "Girl with the Locket". She is a transferree from the 19th District to Sakugawa Middle School and becomes classmates with Uiharu Kazari and Ruiko Saten.

Therestina - a member of MAR first seen in the last moments of "AIM Burst". She operates a mechanized suit of armor which allows her to carry objects many times her weight.

Cultural References
"easter eggs"