After spending a night in Treecko Forest, Gary departed the next morning for Rustboro City.
He wasn't in a hurry and used the trek to train both Shroomish and Treecko. With Treecko added to the team, Eevee's workload doubled, the little fox once again acted as the resident "nanny," running two consecutive training sessions each day—something it had already been accustomed to in previous regions.
During an afternoon break, Gary asked, "Treecko, you've reached the level required to evolve. Do you feel ready, or have you been holding back?"
"Tree…"
Treecko paused. He had never actually considered it. In the colony, every Treecko that evolved had to leave the forest, so they instinctively suppressed the urge.
"You'll become much stronger once you evolve—don't fight the instinct," Gary advised.
"Treecko!"
Treecko closed his eyes, relaxed, and allowed the energy bubbling inside him to flow freely.
A white glow engulfed his body, moments later, he stood a full metre tall, limbs lengthened, three sharp leaves sprouting from each wrist, and a broad, sturdy leaf sweeping back from his head.
Treecko had evolved into Grovyle.
Gary scanned the newcomer:
Pokémon: Grovyle ♂
Type: Grass
Level: 17
Potential: Elite
Ability: Overgrow (Grass-type moves ×1.5 when HP ≤ ⅓)
Moves: Pound, Leer, Leafage, Quick Attack, Detect, Leaf Blade
TM Moves: Solar Beam, Dig, Iron Tail, Rest, Dynamic Punch
Friendship: 255 / 255
Held Item: Soothe Bell
"Oh, you unlocked Leaf Blade—excellent," Gary said, pleased. Leaf Blade isn't the raw-power king of Grass moves, but combined with Grovyle's agility, it enables rapid, surgical strikes—devastating in cluttered terrain. Once Grovyle becomes Sceptile, the forest itself will be his weapon.
"With Grovyle and Shroomish, the Rustboro Gym won't be an issue."
Rustboro's Leader, Roxanne, was a Trainer School instructor who specialized in Rock-types, her overall strength was moderate. The system, however, required Gary to use only Hoenn-native Pokémon, so Shroomish still needed a few more levels.
One week later, Gary arrived in Rustboro City.
Most of that time had been spent training:
Shroomish: Lv 12 → 15Grovyle: Lv 17 → 20
"I wonder what new tech Devon Corporation is showing off—and whether Steven has uncovered any Mega Stones yet," Gary mused.
Hoenn's ancient ruins are littered with such stones. Gary had even brought Aggron along for heavy excavation. Granite Cave near Dewford Town, Steven's favorite dig site, was on his shortlist, another was Meteor Falls north of Rustboro, a cavern formed by an ancient meteor impact. If meteorites landed there once, shards of Key Stones or Mega Stones might still be buried deep inside. A thorough search was definitely in order—after earning the badge.
Three days of rest later, Gary stood before the Gym's doors.
Ding!
New Mission
Earn the Rustboro Gym Badge
Reward: 5 × Mid-Grade Rare Candy, TM — Rock Tomb (permanent), 1 × Premium Silk ScarfEarn the Rustboro Gym Badge using only Pokémon listed in the Hoenn Pokédex
Reward: 5 × Mid-Grade Rare Candy, TM — Rock-type move of your choice (permanent), 1 × Random Battle Item
The layout matched the Petalburg Gym mission exactly.
"Rock-type TMs…" Gary grimaced. Apart from Stealth Rock and perhaps Sandstorm, few Rock moves were genuinely useful.
He rang the bell. A broad-shouldered attendant opened the door.
"I'm here to challenge the Gym," Gary said.
"Of course. Leader Roxanne is inside—please follow me."
Inside the arena, a young woman with twin buns sat reading a book in the stands.
"Leader Roxanne, a challenger has arrived," the attendant called.
Roxanne closed the book, hopped gracefully down to the arena floor, and approached. Her skirt flared as she landed, revealing the pink bike shorts she wore underneath—typical practical wear for Hoenn's tropical climate. Even May favored tights under her dress for the same reason.
Unfazed, Roxanne greeted him. "Welcome. I'm Roxanne, Leader of the Rustboro Gym."
"Gary Oak, from Pallet Town in the Kanto region," he replied. "I'm here for a Gym battle."
"A challenger all the way from Kanto?" Roxanne smiled, eyes bright. "Excellent. Shall we begin?"