Why can't I save her? Each time I travel back to just before Seo's accident, I can never change a thing. Each time, the horrible events just unfold the exact same way. The scooter flips over the hood of the bright blue SUV. Seo's body spins through the air, heels over head. Her long black ponytail fans out from behind her helmet. Then, suddenly I lose sight of her. I run up the slight incline of the street, and the next thing I encounter is heartbreaking. No matter how many times I watch this happen, it never hurts any less.

Her face is so battered, I can't understand what it came in contact with between the vehicle and the curb. Her helmet was supposed to be a life-saving device. It was crushed in the front and on one side, and I feel angry against the manufacturer.

Moments later, I'm also angry at the paramedics who won't let me ride to the hospital with them. I know it's already too late. I watch myself -- two years younger and shaking -- kneel next to Seo as the medical team calls the time of death. The ambulance doors shut me out from my own life; the one I already lived two years ago. And a dozen times more, each time I attempt to change the course of events. Why can't I save her?

"The past is the past," Seohyun smoothed down Niu Nai's unruly short hair. The contrast of dark bristly black against the pale blue of Niu Nai's pillow, reflected into the lenses of Seohyun's glasses. Frequent visits to Niu Nai's time had somehow worsened Seohyun's eyesight. The couple had discovered various ailments caused by time travel. Seohyun's previously twenty-twenty vision had weakened, she suffered frequent headaches, and the worst was the acute nausea she endured upon returning to her own time. Niu Nai had traveled many more times than Seohyun had, especially in the initial phase of her research. Before she'd been able to get Seohyun's help to tweak and improve their project, she'd already started to feel tightness in her joints and at her temples. 

They didn't understand why Niu Nai managed to stay in the past for a few hours, but space-time continuum wouldn't allow Seohyun to follow Niu Nai to her time for more than a few minutes. 

Once the couple had been reunited and seen the ill effects on their health, they made a pact to limit their travel. It was decided that even if Seohyun wasn't manifesting as many health issues, it would be wise to be proactive. As a result, Seohyun decided to use those precious moments to tell her lover goodnight as Niu Nai drifted off to sleep. The short lapse of time enabled her to sneak into Niu Nai's bedroom, and surprise her as she was falling asleep in her pale blue sheets and warm duvet.

"What's done is done, sweetie. I died...er...I will die...I mean..." Seohyun struggled with her grammatical tenses. "Stop trying to change the past. You can't save me. So let's just enjoy the limited time we do have together, hmm?"

Niu Nai sighed, staring at her reflection in Seohyun's glasses.

"I have to go," Seohyun whispered.

Niu Nai nodded and to her side. She wrapped Seohyun's arms around her and closed her eyes.

"Goodnight, baby," Seohyun kissed Niu Nai's cheek and lay in the blue bedsheets, spooning her. 

On these rare nights when Seohyun time-traveled to say goodnight, Niu Nai was lulled into a deep, restful sleep. By the time she fell into slumber, though she could still feel Seohyun's arms on her skin, she knew her girlfriend had already disappeared back into the past.

Years passed exactly like that; with short bursts of Seohyun at bedtime. The inevitable result of trying to preserve Niu Nai's deteriorating health was the almost imperceptible changes in Seohyun's health. Seohyun didn't notice a huge difference, but to Niu Nai -- who, now only saw her once a month -- there was quite a marked change.

Niu Nai vowed to find another way to stay in each other's lives.

As luck would have it, a happy accident occurred one day. The two young women found a way to meet in an alternate time where neither of them had yet ventured. This was a place they both could call the Future.