Rescue the girl! is the second mission in Size Matters. After Luna led Ratchet and Clank through the Jowai Resort, Captain Qwark appeared, trying to conceal himself in the paper he was reading until Clank recognized him. As Clank tried to get Qwark to explain why he was there, Qwark was left bawling as he revealed he never knew his long-lost parents. Shortly after Clank suggested to Qwark he should try to find them, enemy robots confronted them and captured Luna, stowing her away aboard their ship. Ratchet and Clank set off to rescue her.
Two titanium bolts can be obtained during this mission, one prior to the zipline hill, and one behind a hut later in the mission.
The Gadgetron vendor can be used to refill on ammo. To begin the mission, walk on past the hut the technomite dropship blew up and prepare to fend off more scuttle crabs and several guard torsos and Robotic Control Units. The guard torsos are ranged enemies whose shots can be dodged by strafing, while the R.C.Us are smaller spider-like melee enemies. Guard torsos will often leave an R.C.U. behind upon defeat, so watch out for them as their small size makes them easy to overlook. Use the Lacerator on both enemies, or the Acid Bomb Glove on larger groups, as the acid still affects the guard torsos even if they float. Continue along the path, and you will eventually run into a dead end with a grav-ramp, which can be walked on using the Gravity Boots.
Upon reaching the top section, attack the robots ahead. Head forward to a zipline on the right that will lead Ratchet down to the lower platform, where more enemies are encountered. Destroy them and then proceed on into the small cave, where Ratchet will find several crabs and some robots. Upon exiting the cave, Wildfire gloves are obtained. Defeat the four crabs that appear from the water. This area marks another checkpoint.
Hop onto the raft that will take you to the island ahead. On the raft, use the Lacerator to defeat robots that appear on the way, until Ratchet reaches a new island. This island is swarming with crabs, and more will repeatedly jump out of the water from all sides. Defeat them all for experience, and then head forward to find another raft that will continuously lead Ratchet through the waters until it reaches a dock. Along the way, hop across to the nearby islands passed to shoot down any robots that attack and smash crates for bolts, nanotech, and ammo. Upon reaching the dock, fight through another area and defeat the last group of enemies. Finally, to the left is an elevator; take this to complete the mission, after which you automatically travel to Ryllus for the follow-up mission "Investigate the artifact".