The first key is locked in the top-most cabinet behind the grid of white blocks.

Take a closer look at the paintings on the wall. No, closer than that! Specifically, the black framed one.

Notice anything funny about any of the numbers? That 5 is lookin' pretty shifty, don't you think?

Take note of the arrow pointing to the right at the top of the number 5, then return to the top cabinet, Scooby Doo, 'cause we got some work to do now.

Working from the bottom up, click each square in order so that the progression of depressed squares follows the design of the 5 on the painting and ends in the top right corner. From left to right, then up a row, then right to left, then up another row, and left to right again.

Key get! I knew you were smart. We should hang out like these more often. You and me, solving puzzles and crimes! Maybe we could get business cards and matching fedoras and... what?... oh, the puzzles. Right. Sorry.

The second key lies locked away behind the numeric keypad in the middle cabinet. I guess you could say... it's mathematical.

Where have you seen any math-y type symbols?

Hey, didn't the first cabinet you got your first key from have some numbers and symbols inside? Maybe you should go check those out.

Yes, those sure are some numbers and symbols written inside the top cabinet. But how are you supposed to make anything out of them? Maybe there are some directions posted nearby.

Take another peek at the artwork hanging on the wall. There's no accounting for taste, but is there anything there that looks like it might be pointing the way?

Hey, that red painting sure has a lot of arrows. Almost like they're pointing at things in a specific order! Maybe you should write them down.

Returning to the top-most cabinet, apply the arrows to the numbers so you get a math problem. The way each arrow points tells you what number or symbol to look at. In this case, left, down-right, up-left, right, down-left, up-right.

Or, to put it another way, following the arrows to their corresponding numbers and symbols should get you a problem that looks like 81x5+3.

If you solve 81x5+3 using that magnificent brain of yours (or a handy-dandy calculator) you should get 408. Pop on down to the middle cabinet and enter that into the keypad, press E on the pad, and then bask in the success of having the second key!

The third key is behind the lock on the bottom cabinet door. I can almost taste it, can't you? Mmm, tastes like another puzzle!

This last puzzle consists of five squares in a row whose colour you can click to change.

You'll notice that between each square is a symbol. Specifically, the mathematical symbol for "less than". Mysterious!

Have you noticed anything particularly colourful in the room?

Those paintings on the wall are sort of mis-matched, don't you think? They're all different sizes, and the frames have different colours to boot. Maybe you should take a closer look at them.

Say, there are five paintings, which makes five different colours... exactly what we need to solve the puzzle! But we can't just put them in any old order.

Remember, each of those squares on our third and final lock had a "less than" or "

From smallest to largest, the colours of the painting frames are blue, red, black, white, green.

Head back over to the final lock and click each square to cycle through the colours until you have them in the proper order. Once you've entered the proper colour sequence (blue, red, black, white, green!), the lock will spring open and reveal your bounty... the final key!