"I.o." (Tonari: 212) is the 167th chapter of the One-Punch Man manga series.
Short Summary[]
The instant before Saitama's and Garou's punches collide, Blast opens a hyperspace portal and teleports the two above Earth's atmosphere. The impact releases immense energy, endangering the Earth beneath. With the aid of interdimensional allies, Blast redirects the destructive energy away, saving the planet. The recoil of their punches sends Saitama and Garou to Jupiter's moon, Io, where their battle continues.
Long Summary[]
Before the moment of impact between the two Serious Punches from Saitama and Garou, Blast opens a gateway beneath them and teleports them and also Blast himself to space. After being teleported outside Earth's atmosphere, their fists meet and release a gigantic amount of energy. Blast desperately holds on to keep the gateway's form and save the planet from the impact of their punches. He is then joined by his interdimensional allies. As they comment their amazement at someone other than Blast surviving such divine power, they aid the S-Class hero in redirecting the shockwave energy away from the Earth, thus successfully saving it. However, as a result of the recoil of their own attack, both Saitama and Garou are sent flying (in the same direction) far into space.
The two land on Io, a moon of Jupiter; as Garou gathers himself from the surprise of landing on a moon, Saitama makes use of the strange situation, believing he can now go all out. He tries to put Genos' core in his suit but decides to hold onto it, should the suit be torn. When Garou tries to tell Saitama that they must find a way to return to Earth, the hero cuts him off and claims that beating him comes first, directly challenging the Hero Hunter. Surprised by his seriousness, Garou opens a gateway beneath Saitama.
Saitama quickly kicks away the portal from his feet and punches Garou, sending him flying off the moon. However, Garou opens a portal to come back while also opening another one behind the hero to hit him. To his surprise, Saitama grabs the edge of the portal and flips it down, exposing Garou for another punch and knocking him back out onto the surface. Saitama mocks his "little tricks" and asks Garou to use his fists.
Opening numerous gateways to surround Saitama for an attack, Garou speeds through them all and barrages him with his techniques. He uses Roaring Aura Sky Ripping Fist, followed by Water Stream Rock Smashing Fist, which is joined by Exploding Heart Release Fist, before using Whirlwind Iron Cutting Fist, mercilessly pummelling the hero. Garou ends his assault with Nuclear Fission Gravity Knuckle, causing a huge explosion that decimates Io.
With his suit torn but remaining unharmed from the assault, Saitama retaliates with one of his serious moves, Serious Table Flip, digging his hand into the crust and launching tens of thousands of tonnes of lunar rock into the air, ripping apart the moon's surface. Caught directly in the attack, Garou helplessly tumbles in the debris, unable to feel the gravity to stay upright. Saitama dashes through the flying debris and surrounds Garou with his Omnidirectional Serious Punch, creating multiple afterimages coming at Garou with a Serious Punch from all directions. To avoid the attack, Garou quickly opens a gateway to escape, only to find Saitama flying through the portal. Saitama punches him out of the gateway, sending Garou hurtling through the destroyed moon's surface.
Garou halts his momentum and positions his body upright. Telling himself to focus and believing Saitama is simply holding the edge between the rocks, Garou opens a hyperspace gate to the moon's atmosphere above the debris. Before he realizes it, Saitama attacks him with another Serious Punch. Seeing that his opponent is limitlessly strong, Garou reasons he can copy him limitlessly as well to win. Both of them proceed to land a punch on each other, causing them to be hit in the face at the same time.