Explore the Colony
You have an opportunity during the shuttle flight to earn some Paragon or Renegade points, the conversation lines to take for each should be obvious!
Time to search the colony for clues about the human disappearance.
Move into the room directly ahead (don't jump when the lights come on!). Follow through the next door outside onto a gangway. This leads sown some stairs into a large, flat area. There is not much to see here, so continue downwards and through the large bay doors where you'll get your first enemies of the colony. These are LOKI Mechs and FENRIS Mechs, each much tougher than the ones we encountered earlier (though they still shouldn't pose a problem).
Take out the LOKI Mechs behind the barricade and move into the room. As you deal with the LOKI Mechs on the stairs, watch out for a four-legged dog-like FENRIS Mech that will come galloping at you (use Pull on it if possible). With the area clear, collect the ammo and head up the stairs. Go into the building with the open door. Bypass the wall safe and collect the medi-gel.
Once back outside you can salvage some spare parts to the left, but first you should look out for a LOKI Mech and a FENRIS Mech. Again, use Pull to take the aggressive dog out of the equation.
Use Jacob's Pull ability to keep the FENRIS Mechs at bay.
With the route ahead cleared, proceed into the next room. Here you'll run into some Quarians, all of whom are thankfully friendly, and one of whom is a familiar face (or mask) from the first game. They need you to find one of their own, who, while taking part in a Quarian rite of passage, had lost contact with his home. That's why these Quarians, including Tali, are here.
The Quarians are going one way, while your team are going another – this should increase the chances of finding Veetor. Head back outside and into the next room. Be sure to hack the wall safe in here, but watch for the LOKI Mech hiding cleverly underneath it. Once outside again you will have some Assault Drones to deal with. These are particularly tricky due to their explosive rounds. They also have shields, so Jacob's abilities won't work. Miranda's Overload will, however.
With the Drones down continue through the colony buildings. Pick up the med kit in the first, and pass straight through the second. Take the metal steps down and hide behind the cover half-way. More Assault Drones. Take them out and continue back to solid ground. Pick up the medi-gel nearby.
It has emerged that Tali's friend Prazza has raced on ahead, and is currently being torn apart by Veetor's hacking ability. He has programmed a Heavy Mech to deal with them. Of course, we have to be the ones to sort this out. Move to the bay door when prompted, and set Jacob and Miranda on either side of it using the team orders (DPad Left and Right on Xbox 360). Take cover yourself in the centre.
After Prazza gets her just-desserts in the cut scene, you are thrust into action. This is the first 'boss' in the game, but if you play intelligently it should cause few problems. Your team has changed position since you last had control, and the YMIR Mech is a formidable foe. Watch out for destructible cover, but your priority should be to get Miranda to use Overload on the mech to take out its shields. With this done, proceed to take down its armour, and finally its health.
Be sure to pick up the Iridium canister and the Heavy Weapon Ammo Upgrade on the broken remains of another mech nearby.
Be careful of the mech – don't let it get too close
Get the med kit from the nearby building with an open door, and take note of Tali and her remaining companions inside.
Go back outside and locate the colony building with the sealed door, but which has a green light on it. You've found Veetor. Either console or intimidate him into showing you what he knows. You have the opportunity to perform Paragon or Renegade actions here, by pressing LT (Paragon) or RT (Renegade) when prompted during the scene (Xbox 360 controls). Another opportunity to be nasty or nice comes when deciding what to do with Veetor – you can opt to try and force him back to Cerberus, or just take his Omni-tool and suck up to Tali by asking if she will join your squad (she won't!).
Return to the Illusive Man
You will find yourself back in space and talking to the Illusive Man again. Veetor's revelation that the Collectors are responsible for the disappearing humans is a worrying one. Ask the questions you want answered before the Illusive Man tells you that he wants you to investigate this issue. He's selected some possible candidates to join your team to help. You can ask the whereabouts of your old team for some interesting backstory. The Illusive Man suggests you go to Omega to find your first new teammate, a scientist who can work on the research department of your vessel. He also introduces you to a new friend, or more correctly, two.
Guess who (and what) is back.