Magia Record Story Deliver to the Beyond, A Piece of Hope
The following is a summary posted on 4chan's /pmmm/ general.
Yachiyo and Mifuyu met at 12, just shortly after they contracted. Yachiyo initially dislike Mifuyu for being a crybaby and blaming others without trying her best. This changed during a chance meeting where her grandma brought them to the snack shop (same one as Jun's story and where Mikage met mute).
She learnt that Mifuyu was forced to learn at least 9 form of arts after school since hers is a famous traditional family, and her attitude soften more when Mifuyu saved her ass from two PMs who though Yachiyo is here to kill steal, backstabbing and wounding her heavily.
Yachiyo returned the favor when the pair led the witch to finish the girls off, and they left the barrier together. They became closer after Mifuyu visit the Mikazuki Manor under Nanami Grandma's invitation, enough for the two to share their reason for contract,
They join forces after seeing a friendly hostel girl (Mikazuki manor served as one for school girls back then) being kissed by a witch, defeating it. They note that this witch is the same as the one they faced before.
Yachiyo note that they need to train to get strong, and the best way is for two noobs to team up and watch each other's back. Mifuyu is grateful and happy for this invitation, and this ends the first part.
P.S Yachiyo is doted not just by her grandma, but by the students living in the hostel as well. She worked hard to repay their trust and love. Same for her modelling career where she earned the trust of her team by her professionalism and hard work..
Mifuyu is a crybaby overworked by her overbearing mom. So her being a neet now might be backlash. Then again, their MSS showed how Yachiyo stand up for her against her mom, so much so that she was banned from her household, but enough to allow her to visit the Mikazuki manor regularly.
While Yachiyo and Mifuyu gets better at the magical girl business, their life went for a nosedive.
For Yachiyo, her talent turned her team into background, splitting the team into ex-leader supporting her for her hard work and bringing more work, while others hating her being better. This eventually led to the team disbanding since they agree that Yachiyo shines better solo.
Mifuyu gets overwhelmed by real life and magical girl business, combined with how her mom has been trying to ground her ruined her ability to have good dreams.
Their wishes were wasted, and they were nearly killed during a witch hunt thanks to backstabbed by the previous duo of PMs. One of them died, the other get smacked away.
Yachiyo and Mifuyu managed to kill the witch to protect the girl in Yachiyo's modelling unit. But the other PM took the GS from the badly wounded girls.
They almost lost their will to live until they saw the girl they saved, and agree that protecting what they deem as important will not change even if their wishes were moot. Yachiyo remembered that her grandma manage to maintain a positive outlook in live by reading letters written to her by her husband, son and grandchildren, so Yachiyo suggests Mifuyu and her do the same.
These letters ensure their dreams and hopes will be remembered and inherited, allowing to to have the will to live for 7 years. They regret not roping in Kanae and Mel in time.
Putting a brave front, Mifuyu suggests that they should stop writing the letters to cast away their weakness, but Yachiyo thinks it reminds them of their weakness, while at the same time giving them strength as they carry on the wishes of others.
Mifuyu cried like she did in the past, happy that she can rely on Yachiyo again while they both thank each other for everything, and continue well being in the future.
The manage to find more stuff, like grandma's writings, Yachiyo's unsent love letter etc. As the rest of the team returns, Yachiyo hoped that no further sacrifices will be needed, and everyone can live on with hope despite the hardships.