Death Note Black Edition #3

Things are starting to spiral out of control for Light. L captures Misa and detains her, suspecting she's involved, but Light devises a plan: he gives up ownership of both Death Notes—his and Misa’s—in order to lose all memories of them and rescue her. At the same time, a group of criminals known as “Yotsuba” emerges, somehow in possession of a Death Note. Who are these people, and why do they have one of the notebooks?