#st5 speculation

Your little brother, Oliver, sat on the living room carpet surrounded by blocks, plush toys, and a plastic dinosaur army he had been arranging with very serious concentration. Steve sat cross-legged across from him, elbows resting on his knees, watching the toddler with the same focus he once used when planning how to break into a secret underground lab.

“Okay, little dude,” Steve said, picking up a bright blue block. “Where does this one go? I’m guessing… top of the tower? Very architectural. Very modern.”

Oliver blinked up at him with huge eyes, then plucked the block from Steve’s hand and firmly placed it on the side of the tower, causing the entire thing to wobble dangerously.

Steve froze. “Oh, okay, that works too. We’re doing abstract design. Love that.”

You leaned against the doorway, arms crossed, unable to stop the warmth spreading through your chest. Steve didn’t know you were watching—he was too busy trying to stabilize a block tower that was, by all known laws of physics, seconds away from collapse.

Oliver, giggling, slapped another block on top. The tower immediately crumbled.

Steve gasped dramatically and threw himself backward as if he’d been struck. “Oh no! Disaster! It’s gone! The whole city is destroyed!”

Oliver burst into delighted laughter, clapping his tiny hands. It was a ridiculous scene—you never expected the former King of Hawkins High to throw himself on the floor because a toddler knocked over some blocks.

But here he was, doing exactly that.

You pushed off the doorway and walked in quietly, but Steve noticed you when Oliver crawled into his lap and bounced excitedly. Steve looked up at you with a sheepish smile, his hair slightly tangled from where Oliver had grabbed it.

“Hey,” he said, his voice softening. “Your brother and I are having a very serious architectural meeting.”

“Oh yeah?” you teased, settling down on the carpet beside them. “Looks intense.”

“It is,” Steve said with a nod. “This guy’s a visionary. I mean, look at this.” He pointed at the scattered blocks with a proud dad-like expression. “He’s breaking boundaries.”

Oliver reached out toward Steve’s face, patting his cheeks clumsily. Steve gently held his tiny hand, laughing under his breath.

You felt a tug in your chest. Something deep, warm, and so unexpected you almost leaned away from it. Watching Steve like this—gentle, patient, completely smitten with a toddler who kept mispronouncing his name—it did something to you.

And the worst part? Steve had no idea.

Oliver decided Steve’s hair needed rearranging, so he grabbed a handful and started patting it down in random directions.

“Yep,” Steve said calmly, “that’s… perfect. A new look. I’m trusting the process.”

You covered your mouth to hide your smile. “You’re really good with him.”

Steve shrugged, cheeks flushing slightly. “I like kids. They’re easier than monsters and teenagers. Plus,” he added with a teasing glance your way, “your brother likes me more than Dustin does. That’s a win.”

Oliver leaned his head against Steve’s chest with a sleepy sigh.

Your heart squeezed so hard it almost hurt.

Steve swayed gently, rocking Oliver without even thinking about it. “Guess we played him out,” he whispered.

You nodded, unable to look away. “You’re kind of… amazing with him.”

Steve met your eyes, warmth spreading slowly across his face. “Yeah? You like seeing me like this?”

Your cheeks warmed. “More than I expected.”

His smile softened into something tender, something that made that swelling feeling in your chest double.

“Good,” he murmured. “Because I like being like this with you.”

And as he held your sleepy little brother in his arms, you realized it wasn’t just baby fever.