Merm4id from D4DJ "Summer Flower Love Dream"

 is a complex publication featuring Merm4id from D4DJ franchise including blu-ray disc, A4-sized photobook, and B2-sized calendar, but those three publications were released on different dates.

The Blu-ray disc was released on August 21, 2020 prior to photobook and calendar being released on December 2, 2020.

The blu-ray includes live action MVs from their two original songs in D4DJ Groovy Mix, ING and Floor Killer.

Summary
Hirajima Natsumi, Okada Mei, Hazuki Himari, and Negishi Ai arrive at a luxurious beach house. Soon after arriving, they are informed that they will be competing in a series of challenges, the overall winner of which will be deemed the "center" of Merm4id. These challenges are interspersed with gravure-type segments that feature all four unit members.

Challenges include guessing what sports each member played in school, cooking omurice, drawing logos from memory, guessing smoothie flavors, a capture-the-flag game involving inner tubes, and guessing items related to their D4DJ characters through touch.

Trivia

 * The title "Summer Flower Love Dream" is derived from each of the Merm4id seiyuu's given names.
 * The first part of Natsumi's name, "夏", means "summer".
 * Himari does not use kanji to spell her given name, but it can mean "sunflower"; alternatively, "茉莉" (mari) can mean "jasmine plant".
 * Ai's name, "愛", means "love".
 * The first part of Mei's name, "夢", means "dream".