Once the camera has panned over to Danger Mouse and Penfold's starting position back in their mailbox you will immediately have to switch to Penfold, crawl to the left through a hole in the wall, climb down a ladder, crawl to the right (to come out another hole in the wall), walk up a staircase, jump onto a vertically-moving platform and a static platform in turn, and collect the first "DM" badge; once you've done so, you'll have to jump onto another vertically-moving platform and a second static platform in turn and collect the second "DM" badge. You will then have to retrace your steps back to the start, climb up another ladder, crawl to the right through a third hole in the wall, drop down to the platform you started on, and walk onto a red button, to turn it green and unlock the door to your left (but, if you walk off it, it will lock it again) - and once you have done this, you shall have to switch back to Danger Mouse, walk through the door, pick up Penfold, and throw him across a gap to a third platform. You'll then have to switch back to Penfold and walk onto another red button to turn it green and unlock another door above you (but for a second time, if you walk off it again, it will lock it again); once you have done so, you will have to switch back to Danger Mouse, jump up to two more platforms in turn, walk through the second door and drop down to the third platform. You will now have to: switch back to Penfold, drop down to the ground, crawl to the right through a fourth hole in the wall, throw two switches to activate two vertically-moving platforms and throw them again to deactivate them once they pass through an electrical force field, switch back to Danger Mouse, jump onto the first (now-static) vertically-moving platform and a sixth platform in turn and collect the third "DM" badge. You'll then have to jump onto the second (now-static) vertically-moving platform and two more platforms in turn, and walk onto a third red button, to turn it green and deactivate a second electrical force field (but if you walk off it again, it'll activate it again) - and once you've done this, you'll have to switch back to Penfold and walk through the (now-deactivated) second electrical force field onto a fourth red button to unlock a third door above you (but for a 3rd time, if you walk off it again, it will lock it again). You'll then have to switch back to Danger Mouse, drop back down to the seventh platform and walk through the third door onto a fifth red button to turn it green and deactivate a third electrical force field (but for a second time, if you walk off it again, it shall reactivate it again); once you have done so, you will have to switch back to Penfold, crawl to the right through a fifth hole in the wall, jump onto a third vertically-moving platform and up to the seventh platform in turn, walk onto that fifth (now-green) button, switch back to Danger Mouse, jump up to the third vertically-moving platform (because Penfold is now standing on the fifth button, this shall have no effect on the third electrical force field) and two more platforms in turn, activate Danger Mouse's grappling hook on the wall-mounted anchor, abseil to the left over the rope, drop down to a tenth platform, throw a third switch to turn off an air vent (which is blowing full blast and cannot be bypassed while it is on), drop down to an eleventh platform and collect the fourth "DM" badge.
You will then have to: switch back to Penfold, jump onto the third vertically-moving platform, activate Penfold's shield, and deactivate it again once the platform has passed through the now-reactivated third force field, jump onto the eleventh platform, switch back to Danger Mouse, pick up Penfold and throw him up to a fourth vertically-moving platform; once you've done so, you will have to jump up to the fourth vertically-moving platform and a twelfth platform in turn, walk up a third staircase, switch back to Penfold and follow Danger Mouse's path, switch back to Danger Mouse, pick up Penfold and throw him at a stack of four crates to smash through them and collect the fifth "DM" badge. You will now have to retrace your path back to the edge of the platform, jump over to a thirteenth platform, walk halfway down a fourth staircase, jump up to two more platforms in turn and collect the sixth "DM" badge - and once you've done so you will have to switch back to Penfold and follow Danger Mouse's path, walk all the way down the fourth staircase, crawl to the left through a sixth hole in the wall, climb up a third ladder, crawl to the left out of a seventh hole in the wall, and fall down onto a sixth red button to turn it green and unlock a fourth door above you (but for a fourth time, if you walk off it again, it will lock it again). You must then switch back Danger Mouse, drop back down onto the fourteenth platform, jump up to a sixteenth platform, walk through the fourth door and down a fifth staircase, throw fourth switch to activate fifth vertically-moving platform, switch back to Penfold, jump onto the fifth vertically-moving platform and a seventeenth platform in turn, switch back to Danger Mouse, jump onto a sixth vertically-moving platform and eighteenth platform, in turn, activate Danger Mouse's grappling hook on another wall-mounted anchor, abseil to the left over the rope, drop down to a nineteenth platform, throw a fifth switch to deactivate two more electrical force fields, drop back down to the seventeenth platform, pick up Penfold and throw him up to a twentieth platform, switch back to Penfold and collect the seventh "DM" badge; once you've done so you will have to drop back down to the sixteenth platform, jump up to the twentieth platform, back onto the fifth vertically-moving platform and onto two more platforms in turn, jump up onto a sixth staircase and walk up it to collect the eighth "DM" badge. You'll then have to drop back down to the twenty-second platform, jump back onto the twenty-first platform and each of the three steps of a twenty-third one in turn, drop down to two more platforms in turn, walk halfway down a seventh staircase, jump up to three more platforms then walk onto a seventh red button to turn it green, and unlock a fifth door below you (but for a fifth time, if you walk off it again, it will lock it again) - then, once you have done it, you must switch back to Penfold, follow Danger Mouse's path up onto the first step of the twenty-third platform, crawl to right through an eighth hole in the wall, walk down the seventh staircase (and through the fifth door), switch back to Danger Mouse and walk onto an eighth red button to turn it green and unlock a sixth door below you, but for a sixth time, if you walk off it again, it'll lock it again. You will then have to switch back to Penfold, walk through the sixth door and down an eighth staircase, drop down to a seventh vertically-moving platform and a thirty-first platform in turn, walk back to the left down a ninth staircase (while watching for two more electrical force fields that activate and deactivate with each second), and collect the ninth "DM" badge; once you do this, you'll have to walk back to the left (while watching out for an eighth electrical force field which activates and deactivates with each second), and walk onto a ninth red button to deactivate a ninth electrical force field above you (but for the third time, if you walk off it again, it shall reactivate it again). You'll then have to switch back to Danger Mouse, drop down to two more platforms and twenty-fifth one in turn, walk down the eighth staircase, turn back to the left (to use Danger Mouse's grappling hook on a third wall-mounted anchor), abseil to the right over the rope, drop down to a thirty-second platform, throw a sixth switch, to activate three more vertically-moving platforms, jump back to the left onto the tenth vertically-moving platform and up to a thirty-third one in turn, throw a seventh switch to unlock a seventh and last door below you, use Danger Mouse's grappling hook on a fourth wall-mounted anchor, abseil to the left over the rope, fall down to a thirty-fourth platform collect the tenth "DM" badge - and once you've done this, you will have to jump back to the right onto the seventh, eighth, ninth and tenth vertically-moving platforms in turn, jump back up to the thirty-second platform and walk up a ninth staircase to the exit. You must now switch back to Penfold, retrace your steps back to the edge of the thirty-first platform (while again watching for the sixth, seventh and eighth electrical force fields activating every second, but deactivating every other second) and follow Danger Mouse's path to the exit; the "MISSION COMPLETE!" text shall then appear displayed on the screen for a ninth time, and the duo will proceed to Episode 10 (the majority of which must be finished with Danger Mouse alone).