Kazuki, known for his lightheartedness, and Rei, a man of quiet resolve, accept a Christmas-time assignment that will irrevocably alter the course of their lives.

The assassins’ existence with their latest assignment is far from easy, a trial compounded by the arrival of a fresh undertaking.

They resolved that it was time for farewells, guiding Miri back to her mother. But first, a final moment of shared space on the playground.

Caring for Miri demands constant attention, a true full-time commitment. Perhaps the children have discovered a solution: daycare. However, securing a place for her will prove more complicated than it initially appears.

Though their daycare venture has finally succeeded, Miri’s arrival is straining the group’s finances. It seems they must now consider taking on additional work.

Kazuki resolved to be a more present father to Miri. However, delving into the details of a scuffle she'd been involved in at daycare risked earning him a permanent place on her wrong side.

With the shift of seasons, a familiar melancholy settles upon Kazuki, a weight compounded by the growing sense of being overworked and overlooked within his own home.

Rei's return to his hometown brings with it a strained reckoning, a difficult demand laid upon him by his father, a man of lethal profession. Elsewhere, Kazuki and Miri are orchestrating a secret, a carefully planned surprise.

At Miri’s daycare, the annual field day sees each of her friends offering quiet encouragement, finding their own ways to cheer her on.

A chance meeting at the daycare center prompts Kazuki and Rei to profoundly re-evaluate their role as Miri's guardians.

The quiet of life without Miri settled around Kazuki and Rei, but it brought with it a different kind of trial. They now confronted a fresh difficulty.

The Christmas party hummed with sound as Miri sang, her voice weaving through the cheerful din. Meanwhile, Kazuki and Rei resolved to confront the organization and finally put things to rest.