This would probably have deserved a 6.5 but it managed a half point more thanks to my inescapable, conscious weakness for Jung Hae In.
The man smiles and I forget myself.
Hopeless.
Besides the hopelessness of my crush, though, I think it is relevant in this context to notice that it did not make me blind to a number of details that all together prevented my full enjoyment of this drama.

First and foremost, the sci-fi element: although this is definitely a romantic drama, I can't help but feel like they threw away a perfectly good sci-fi prompt by savagely mistreating it. The AI device is meant to be a pretext to entangle these characters' lives, and nothing more. Which is very upsetting because the whole idea of a device mimicking a person pattern of speech, and a dead person's speech at that, is so very intriguing and presents the perfect opportunity to push beyond boundaries and explore bereavement and healing and human relationships. Furthermore, they could have easily made it believable given the current state of AI development when, instead, throughout the drama, the technology felt absolutely unbelievable in multiple instances (e.g. I could have believed the Jisoo device becoming aware of itself, although it occurred too randomly and too suddenly for my tastes, but I could not suspend my incredulity when it asked to hear Jisoo's husband's voice, or, again, when it remembered memories that were not input by the owner of the memories themselves).
In my eyes the mismanagement of the sci-fi aspect (which was the reason I was drawn to watch in the first place… ok, maybe second place after Hae In) is an unforgivable sin, especially considering how much it propelled the plot forward in the beginning. A sin that took me out of the story and interrupted its flow and congruity.

The second element that disappointed is character development. I'm not saying it was completely messed up, yet it felt sloppy and, almost, unfinished. One recognizable theme in the story is basically about the capacity to overcome trauma through human connection, but the process that brings each character to their healing is confusing. Motivations behind certain actions were cryptic at times and I seldom understood the reasons for characters' choices or empathized with them. I also believe that the pacing didn't help. In particular with the confrontation that should have been the climax of the story: at that point the tension had completely dissipated and nothing about that scene felt pivotal for the characters.

Cinematography, acting and soundtrack sustain the whole drama and confer cohesion to the narration. The colors, the lights, the locations as well as the melodies work wonderfully toward evoking soothing, pensive, intimate atmospheres.
There isn't any performance that can be considered outstanding, yet the fact that the characters still come through despite imperfect writing attests the solid quality of all actors.
I liked the idea of building a tale of crossed destinies, how it conveys the theory of interconnection and the weight of human relationships, however it felt fumbled, notably with secondary characters (i.e. Min Jung), and some connections were forced (i.e. the one between In Wook and Soon Ho).
The attempt at creating a complex narration through recollection and discovery and a single character that unites all the others and dies early on is compelling enough. Still, I consider it a failed attempt since the character the story hinges on isn't interesting enough to prop everything else.

I believe the show's greatest merit lies in the development of the protagonists' relationship. They come together naturally by filling each other existential emptiness. The other's presence is the necessary prompt to leap beyond the blocks that hinder their growth. And it is heartwarming seeing these people learn how to stand on their own feet by meeting each other halfway (rather than just leaning on the other person).
It takes courage to look at all the pieces we're missing, those parts we lost along with the people that cherished them. We try to cling on the emptiness in fear of forgetting the love we gave and received, in fear of being too damaged to carry on by ourselves.
We need a connection to map out the unfamiliar borders that make up our self, the self that survived the loss.
We need a connection to want to feel complete again.
This is the hopeful message I want to take home from this show and, although I was let down by the clumsy misuse of the great potential of this story (hence the harsh score), I can ultimately say that it was worth watching.

But, most of all, how could anyone not forgive and forget looking at Hae In smiling, though?

Female Empowerment Score (5/5) portrayals of women helping each other always win my favor. Always.