There are some things that people are unable to say while they are alive; for these, there are "shigofumi," letters carried from the world of the dead to the world of the living. When a person with strong emotions dies, they are able to create a shigofumi, whether their feelings are of love, longing, or resentment. It is the quiet and mysterious Fumika's job to deliver these messages from the departed. Along with her talking magic staff Kanaka, she ensures that each shigofumi reaches its intended recipient, even if that person does not want to face its contents. Fumika witnesses the tragedies of people, both dead and alive, and sees their deepest secrets revealed. What is unclear, however, are the details of Fumika's past. Who was she before she came to be a carrier of shigofumi?

Enforcer Teppei Sugou, former ace pilot of the National Defence Army's 15th Integrated Task Force, is visited by a scout from the Ministry of Foreign Affairs and invited to rejoin the military. While considering the offer, he recalls his last months of service. His last mission, Operation Foot Stamp, had been a highly classified military strike against the Southeast Asian Union. The operation quickly went south for the ground forces, and Sugou's First Guardian drone was ordered in as air support to drop emergency supplies for the ground units and then return to base. Following orders against his own judgement, Sugou abandoned his comrades on the field. Many lives were lost during the operation, including Itsuki Otomo, Sugou's commanding officer. However, three months later, following a massacre at the Ministry of Defence, Otomo was spotted at the scene on camera. Now a suspect in an act of terrorism, Sugou cooperates with Enforcer Tomomi Masaoka and CID Division One as they hunt his former mentor down.

Taeko Okajima is a 27-year-old, independent woman who spent her entire life in Tokyo. Looking to unwind from the rush of the big city, she decides to visit her family in the country to help out during the harvest.

On the train there, Taeko vividly recalls her memories as a schoolgirl in the initial stages of puberty, as if she is on a trip with her childhood self. A young farmer named Toshio picks her up at the station, and they quickly develop a friendship. During her stay, Taeko forms strong bonds with family and friends, learning the contrasts between urban and rural life, as well as the struggles and joys of farming.

Nostalgic and bittersweet, Omoide Poroporo takes on Taeko's journey as an adult woman coming to terms with her childhood dreams compared to the person she is today.

[Written by MAL Rewrite]

Miki Koishikawa is a high school student who enjoys a very simple life. However, her ordinary life is about to be turned upside down, and she may not be able to handle everything that is coming her way. After a very "fun" holiday in Hawaii, her parents have decided to get a divorce. As if this wasn’t enough of a shock for the poor girl, she also discovers that they will soon be re-marrying and swapping partners with another couple who they met on holiday. In order to include Miki in this shocking turn of events, they ask her to give the new couple a chance, and set up a dinner date with everyone. Miki may have tried to be emotionally prepared for her new parents, but what she was not expecting was their handsome son Matsuura Yuu. Miki develops an instant crush for Yuu. What starts off as a lovely friendship between them soon develops into romantic feelings which they are both finding hard to control. But more trouble is ahead in their relationship, as both Miki and Yuu have admirers of their own who are trying very hard to keep them separated.