This hits Emotionally!
I started watching this show as I heard this was a sci-fi show based on time travel, as I was really into this genre for a while after recently watching Netflix "DARK". The initial episodes which have a comic genre were really fun to watch, as it gives characters introduction and indirectly makes you love each one of the character.
The second half of the series takes you in the journey of trauma the characters face and the emotional moments they had to go through. You not only watch but live their stories with them. This series makes you love a character show much and then makes you realize how empty it would be without them, just like how the characters feel. Although, the series has a sci-fi genre and smart time-travel techniques, this series main core, the beauty, the reason for keeping you hooked is it's emotional parts, the characters journey and relation to one another.
I can keep on talking, yet words are not enough. But the last thing I would like to note is the beautiful climax/ending. It gives you a satisfaction after all the things you had to go through along with the characters, and even though you know this is the best ending for this characters you still want to see their next every day daily livelihood, it's just very difficult to say goodbye to this characters.