as an idea: the orcs start to target halflings as a similar target to gnomes, possibly including some member of the clerics family. Are there diplomatic relations between the city they're in and the ogre mage? if so, diplomatic break down and/or terrorism campaign...the orcs have gun powder maybe they invent the wagon bomb for market places...take control of the thieves guild attempt assassinations of notable people requiring the PCs to be hired as body guards. The city they're in is gearing for war so the party is drafted into military as a scout group or regular troops...just a few thoughts, hope there's something of use.