[OOC: @nick: In this situation, I don't think it's so easy to take the cube from Ophelia, especially since "hiding it" probably means that it'd need a bit of fiddling to take it out. So you can do the following:
You make a sleight of hand check against DC 25. This already includes Ophelia's (certain) attempt of trying to keep you away from her.
Let's do this first and then we'll see if Ohalian manages to get away from her or not.
@Ophelia: I've calculated the DC based among your skills, the specific situation, etc., so this includes your defense against Ohalian's attempt. Once Ohalian has posted, please post what your PC does next.]
Ohalian sighs again, before walking up to Ophelia, reaching out and trying to grab the cube from where it's hidden.
"When I say I'm going to do something, it means I'm going to do it."
OOC: I do believe that will provoke an attack of opportunity or two, which they could use as disarm attempts.
EDIT: Sleight of Hand check added, as per GM post.
EDIT2: MISERABLE FAILURE![/Unreal Tournament announcer voice]