In the previous chapter, Kalinka and Dr. Cossack went to Dr. Light's lab to thank him for helping Kalinka recover from her "Grown Up Girl" condition in chapter 15.
Now, in the second part of chapter 18, Kalinka, Rock and Roll have some fun together. The Light family attend a fair, among other things. What's more? Forte asks Dr. Wily to upgrade him to be able to fight Super Rush Man following his humiliating defeat in chapter 10.
How does Dr. Wily follow through? You'll have to check out the chapter here to find out!