They had needed her to come back. They had hoped to find and save her from wherever she went. They had needed to find her for Sirius. He hasn't been the same without her. He hasn't joked around with anyone since she left. Sirius blamed himself for her leaving. And now she was gone forever because she's dead.
Hermione and Sirius had dated for two years before she left for some mysterious reason. No one knew why she left but didn't care, they were going to find her. After one year, they finally tracked her down. It was a cold, rainy night and you could barely see a thing. But when they found her she was moments away from dying. When Sirius saw her, he ran to her side to try and save her. They were able to have one more conversation before she died.
Flashback
"Mione, babe. You can't leave me. You have to come back," Sirius cried to her.
"Sirius. It's my time to leave, baby. It's not your fault I left Siri. I went shopping after visiting ma and dad for something I knew you'd love when I was taken. Siri, I want to tell you now that you have a beautiful son at my parents house. He's two months old and needs his dad now more than ever. I was going to tell you the day I was taken that I was pregnant but didn't get the chance. I'm sorry I didn't get to tell you sooner. His name is James William Black. I'm sorry I won't be able to help raise him though. I can already tell he's going to be so much like the both of us," Mione replied.
"That's a great name, Mione. But he'll need his mother and you have to be here for us. I don't know how to take care of a baby. I only watched Harry with Remus or Lily around. We'll need you," Sirius finished, "I'll need you."
"Sirius I'm going to tell you something my mom told me once. I'm always here with you, maybe not in life but in spirit. I'll always be with you no matter what. No matter what people say I'll always be near. I'll be here for you and James and everyone else. I'll watch over you guys from wherever I'm going," Hermione calmly stated.
"Is there any way to trade places with you so you can be with James?" Sirius asked quietly.
"No honey. There isn't. I have to go now. I'll bet heaven's a beautiful place. Take care of everybody but most importantly take care of you and James."
End Flashback
He'll never forget her and he tells his son the same thing she told him when he asks where she is.
She's always here with us.