The setting isthe manga, so the haunted house was the first case the Shonen tantei solved. This takes place right after that, so they aresn'y as cohesive a group as they later became.
"Everybody ready?" Ayumi asked, clutching her flashlight.
"Ready!" said Genta, brandishing his baseball bat.
"Ready!" agreed Mitsuhiko, a bag of snacks slung under his shoulder.
The three kid's stood outside the large foreboding looking house.
"I can't believe Conan chickened out." Genta frowned. Despite his teasing to the contrary, he knew Conan was the farthest thing from a coward.
"Maybe he didn't want to get in trouble with Ran-neechan," Misthiko suggested. Of all of them Conan had seemed the most embarrassed by the tongue lashing he got the last time the four of them attempted this.
The other two nodded. Conan had come across as one of those kids who never got in trouble, he probabely felt really bad.
Shame he'd be missing out on the fun.
It was Ayumi who'd once again found out about the haunted house. There were no scary murderers this time but a real live monster that had eaten the young boy who'd lived there by himself!
Fortunately the inside of the Etou house was nowhere near as scary as that last one. But the rumor wasn't lying when it said the house was filled with books.