Let's see here, episode 3 dealt with a twin girl client whom her twin brother locked himself in his room due to a virus presence. There's a bit of a plot twist in the end though!
And episode 4 is a MUCH needed flashback episode since it deals how Sumire got involved with viruses [spoiler]which was due to getting her finger pricked on Lucia's brooch.[/spoiler] And we get to see the first time Sumire goes to her berserked form!
This series is starting to grow on me, and I'm obviously watching it just to see Lucia's and Sumire's relationship grow.