My son saved his 5-year-old sister as an organ donor; 13 years later, she received a birthday card that said, “Happy birthday, little sister.”

I thought I was prepared for every emotion that would overwhelm me when I saw my daughter turn eighteen.

I was wrong.

That morning, our little house smelled of vanilla cream and fresh fruit. She had been awake since six in the morning, hanging paper lanterns on the porch and trying not to cry.

Hannah was eighteen years old.

My girl. The daughter for whose life my son Luke had given everything.

—Mom, are you really crying yet?

Hannah was at the kitchen door, her hair tied up in a messy bun.

—I’m not crying. I’m just allergic to birthdays.

He smiled and put his arms around my waist.

—Your brother would be very proud of you —I whispered.

—I know, mom. I’m sorry. I always feel it.

A few hours later Hannah’s best friends, Ailani and Skylar, arrived, with gifts and enough excitement to fill the entire house.

When Hannah came downstairs in her new blue dress, the girls screamed with excitement and hugged her.

I stayed close, trying to remember every moment.

For thirteen years she had raised Hannah practically alone.

Her father, Victor, left when Hannah was just a little girl and Luke was still a teenager.

I stopped waiting for him to come back.

When Hannah was nine years old, she asked me about him.

—Did you love us, mom?

—I think I loved you the best I knew how, honey. It just wasn’t enough. That’s their responsibility, not yours.

He nodded and never asked again.

That afternoon had to be dedicated to the cake, the gifts and my daughter, who was becoming an adult.

—Alright, this one first —Hannah said, approaching the pile of gifts.

His fingers stopped on a simple white envelope.

—Whose is it?

—It’s not ours —Ailani said.

Skylar shook his head.

—We found it in the mailbox. It was addressed to Hannah.

Something in that envelope made me feel a knot in my stomach.

Hannah opened it.

A photograph fell of him.

—Mom.

I approached.S

Hannah was pictured at the coffee shop where she worked, taken just three days earlier from across the street.

—Did you do this? —asked.

—No. I had never seen that photograph.

He unfolded the card.

His hands began to shake.