This is a must-watch if you're in for a heartwarming love/family story without the stupid draggy drama tropes.
Bound to give you some inspiration in life and some words of encouragement.

The premise is very simple: like the original US film 17 Again,
18 Again is about the male lead being unhappy with his life and his body suddenly goes back to when he was 18
So you have two actors (one "old" and one "young") playing the same character
and learning about what it means to appreciate the mundane daily life
and what it means to love someone even when real life gets hard
(but like, realistic "trying to make enough money to live" "trying to chase after your career dream" hard, not "chaebol mother kimchi slaps" or "ultimate bad guy is here to kill us all" hard)

10/10 to the acting because Lee Do-hyun absolutely slayed!
Playing a 40+-year-old soul in a 18-year-old body, he really did have that chemistry with his costar Kim Ha-neul
The way he looks at her with so many mixed emotions and the way the characters interact really makes me forget that Lee Do-hyun is a young new rising star.
Of course the other actors also added a lot to the story telling. I don't think there's a bad apple in the cast at all.