"Why did you die in my place?!" "Because you're the only family I have left." "Even so, we're not even blood-related." I died in place of my precious friend, who was like family to me. And yet, I regressed?! Even if I die in her place, the destined future is humanity's destruction, meaning Gyeol is still going to die. The only way for both of us to survive is to prevent humanity's demise. I will never let Gyeol die! This time, I'm going to live happily! It's my first time regressing, but I'll become the ultimate support and work hard to get strong!