Plot bunny

Perry Mason type gets hired by someone facing a murder charge. He reluctantly accepts (only because of old promise or some such). In the end, he gets the guy off by proving he was somewhere else at the time.

As he gets found not guilty, lawyer tells him he's kept the promise. But the guy will have to get a new lawyer....

Y'see, the somewhere else that the guy was was murdering someone else... 🙂