-( Story related, cannot be missed )-
This wraps up the first case you're given during the entire game and, as such, is impossible to miss when completing the entirety of it. I have written up the steps necessary to complete the case, so feel free to look in the spoilers if you wish to find out.
*** Spoiler - click to reveal ***Act 1: Sweet Sweet Magic
Part 3: Wizards Only!
Inside Ron James's shop at night, the first task is to head downstairs where the party's taking place. The only thing that looks really suspicious are the doused candles near the bookcase. Head far to the right to fish out a club from the umbrella rack, then use it on the dripping chandelier near it. Run back to the left and use the makeshift torch on the fireplace, then use the lit torch on the two candles to get in. Once down in the pits, first check on the manhole beside you to get the manhole cover. To the left, all that you can truly pick up is a rusty hook, while to the right, you can use the manhole cover to get closer to the pullchain to the door. Return back to the uncovered manhole you made and travel down it. Along the right path you can open a toolbox for a wrench and find another snail on the pipeworks.
Return back to the Ice King and combine the hook with Jake. Use the combined item on the pullchain and let the Ice King in. While he's tending to that, return back to the shop and head right. Use the wrench you uncovered from the toolbox to loosen the valve wheel, then return to the sub-level of the pit and use it on the open spot on the far right pipe. Use the wrench to tighten it, then turn it to open the pathway on the far left. Entering this is the back entrance to the prison. Talk to Mr. Creampuff to get the wand case key, then you're free to leave from the main door. Now, go into the door Ice King was standing in front of earlier to find that he's been held prisoner. Venture to the far end of the room and sever the rope with your sword, then use the wand case key on the case nearest to the wizards that are distracted. With the case open, simply replace Bufo's wand with Abracadaniel to finish the case.