It was released through Big Hit Entertainment and Republic Records on October 26, 2020, five months after its predecessor, The Dream Chapter: Eternity (2020).

Following the conclusion of the three-part "Dream Chapter" series which depicted stories of growth,[4] Big Hit Entertainment posted a motion graphic video on YouTube and Weverse on September 21, 2020, which revealed that Tomorrow X Together would be releasing their third EP, Minisode1: Blue Hour the following month.

[8] It begins with vocal harmonies and vintage sound in the chorus before advancing in a melodic arrangement of electric guitars and synthesizers.

Driven by electric guitars in the bridges and bass-filled dance breaks in the segments, the soft and breezy track features smooth vocals from the band.

[8][14] The song's Korean title (5시 53분의 하늘에서 발견한 너와 나) is a reference to the time 5:53 PM, which is the golden hour in the city of Seoul in the month of October.

[8][10] Metaphoric to the complex colors of the sky just before the sunset, the lyrics celebrate "the desire to revisit beautiful past memories via one's imagination.

"[1][10][14] Explaining further on the theme in an interview with Elle, Soobin stated, "The scene is mesmerizing, but it's also too dark to recognize and 'know' the people around us, including our friends.

[10] The third track, "We Lost the Summer" (Korean: 날씨를 잃어 버렸어) is a dancehall number with tropical influences, that was co-written by British singer-songwriter Charli XCX.

[10][11] Inspired by the 1998 Korean pop song "Arcade" by Han's Band, which focussed on the financial crisis of Korea in the '90s, "We Lost the Summer" parallelly speaks of "teenagers who face a world flipped upside down due to the pandemic.

"[8] The fourth track, "Wishlist" is an uplifting and anthemic guitar-driven pop-rock song, co-written by Huening Kai, Taehyun and Yeonjun.

[1][8][13] The closing track, "Way Home" (하굣길) is a future R&B song knitted with a soft vocals, trap beats, rhythmic drums, and synthesizer harmonies.

"[18] The goal for the visual aspects of this album was to reflect the development of the online space as our hub of communication and togetherness while physically being home.

It's become much more natural now to meet people and spend time with one another online; it's a change in our culture and the definition of the "space" we share with our friends.

[32] A few hours prior to the album release, the band held a media showcase at the Yes24 Live Hall, Gwangjin-gu, Seoul, which was broadcast online through YouTube.

[37] Tomorrow X Together began promoting the album with televised live performances on several South Korean weekly music programs, starting with Mnet's M!

[39][40][41][42] They performed "Blue Hour" and "We Lost the Summer" on Kakao TV's Comeback Show MU:Talk Live on November 2.

[45][46] Tomorrow X Together released a group teaser for the music video of the album track "We Lost the Summer" on November 10, 2020.

Choi Ji-won from The Korea Herald labelled the EP "very poetic and stirs up listeners’ emotions, as did the band's previous music."

"[11] On the other hand, Lim Seon-hee from IZM deemed the track list as "easy listening" that still see the group "spread[ing] bright and plump energy [...] which takes a breath away.