Why?

Prologue

Chase's POV.
I woke up again for the fourth time as he flipped on his side to look at his alarm clock, to see it was 4:27. I finally decided to wake up as he picked up the clock so his alarm wouldn't go off at six before going downstairs and turning on the coffee machine before flipping the light on and started making pancakes, which I decided that I would eat some, then save the others for Kaz, Bree, Skylar, and Oliver, due to the babies being to young. Just as I finished, I heard a scuffle from outside of the door, making me put my coffee mug down and stand up before I heard crying, making me panic, I immediately ran to the door and opened it, only to look down and see a basket with a baby girl in it, wailing as her tiny arms flung around and she kept squirming. I picked her up, gently rocking her and stroking her hair as her wails reduced to small sniffles and a occasional tear running down her cheek.
"Don't cry. You're ok." I whispered as I wiped the last one off her cheek with my thumb before she fell asleep contently in my arms as I smiled, grabbing the basket before closing the door.
"You can't be older then a few days old. You don't look that healthy either." I realized, putting the basket beside my chair as I continued eating before I heard people coming downstairs, and it was Kaz, Bree and Isabella
"Hey Chase. What's for breakfast?" Kaz asked, bags under his eyes due to Isabella having trouble sleeping like, well, a baby.
"Pancakes. I left them in the oven on warm for you guys." I explained as I looked at my older sister who was in shock as Kaz pulled Isabella in her high chair.
"Chase...who is that?" She asked, referring to the baby.
"Oh. I have no idea. I couldn't sleep last night, so I went ahead and made breakfast when I heard scuffling noises outside. I went to go see if everything was ok when I heard crying, so I ran out there and found her." I explained.
"Do you think it's your kid?" Bree asked.
"No, that's ridiculous."
"You sure? Cause I know how you felt about Sel-"
"Bree, we hated each other. Now stop it." I replied, feeling my cheeks turn red in embarrassment, looking down at the baby before asking.
"Why would someone do this to her?"