The sun burns bright on a Hawaiian beach, as Mallory chases Diego. Laughing, she tackles him and pins him onto a towel by their parents, and Chloe.

"Let him catch his breath," Cristina says, eyes on her book. "And you should take a break too, I don't like the sound of your breathing."

"Aw Mom!" The redhaired girl flops onto a beach chair.

Giggling, Diego rolls over and looks at the sky.

"Anyone need more sunblock?" Owen holds up a tube, looking pointedly at Mallory.

"Fine, fine." The ten year old girl takes the lotion from him, and starts applying it to her thin arms.

"How about you?" Owen grins down at Diego.

"I'm okay." He smiles up at his father. Just four years old, he has never known a family vacation as fun and sunny as this one. "Can we build another sandcastle?"

"Have some water first." Cristina hands him a bottle.

Diego sits up and drinks some of the cool liquid, then puts the bottle into the cooler. He props up his head on his knees and looks at his father's legs. Curious, he reaches out and traces the winding scar on Owen's right leg. "What's this?"

"That's a scar."

"I got one too." Diego looks down at his brown chest, neatly divided by a raised line.

"I put it there," Cristina reminds him. "I fixed your heart."

The boy smiles, and touches his scar. It always makes him feel close to his mother. Then he examines Owen's leg again. "What happened?"

His father grins. "I cut my leg in an automobile accident."

"Did it hurt?"

"Not much." Owen's eyes twinkle. "It hurt the most when it was sutured."

"Because you were too macho to let me numb you first," Cristina drawls.

Diego stands up and touches the scar on Owen's forehead. "What happened?"

"I ran through a glass door by accident."

"I have a scar." Mallory lifts her bangs and shows him a small scar below her hairline. "It was Chloe's fault."

"It was not!" Chloe scoffs. "You were the one who ran into the table."

"Because you were chasing me!"

"Because you wouldn't leave me alone!"

Owen winks at Diego. "They could go on for hours."

Cristina motions to Mallory. "Here, I'll do your back, before you burst into flame."

"Ha ha." She shifts over and Cristina starts applying the lotion to her back.

Diego's fingers go to the circular scar on Owen's left shoulder. "What happened?"

His father's face turns serious. He quickly glances at Cristina before responding. "I was shot."

"You what?" Chloe puts down her tablet, as Mallory turns and stares.

Owen half-smiles. "It was a long time ago."

"Was it in the war?" Mallory asks.

"No ... it was at Seattle Grace." He speaks slowly. "A very sick man was angry over his wife's death. He came to the hospital for revenge. He killed some people before he killed himself."

The children stare at him while Cristina ducks her head and continues massaging Mallory's back.

"Why did he shoot you?" Chloe asks.

"He tried to stop the gunman," Cristina says quietly. "He was a hero. The man would've killed more people, if it weren't for your father."

"Your mother was a bigger hero," Owen insists. He glances again at Cristina and she shakes her head. "Anyways, it was a clean through-and-through. I healed very quickly."

"Do you have any scars, Mommy?" Diego asks.

"I have a couple." She stands up and lifts her shirt, pointing to a faint line on her abdomen. "That's from an icicle."

Owen leans over and peers at it. "You can barely see it. You had an excellent surgeon."

"He wasn't bad." Cristina winks at him. "I'd say, adequate?"

"'Adequate'?" Owen grins. "Did I not just win the National Safety Council Surgeon's Award for Service to the Safety?"

"Here we go." Mallory rolls her eyes.

"It's like Mom and her Harper Avery award." Chloe laughs.

Chuckling, Owen stands up. "Who's ready for some sandcastle building?"

"Me!" Diego grabs his pail and shovel and scrambles to his feet.

"Me!" Mallory jumps up. She turns and looks at Chloe. "You coming?"

The tween puts down her tablet. "You bet."

"Have fun." Cristina picks up her book again.

Diego puts down his things and flings his arms around her neck. "Come play! Pleeease!"

She looks at his sparkling dark eyes, his happy grin. Not for the first time, she reflects that his infectious smile will make him very popular when he becomes a teenager.

"We'll build the best castle!" Diego promises her. "Nobody will have one like ours!"

"You know how to push my buttons," Cristina laughs. "Okay."