End with a point that launches the reader forward. At the end of the Introduction readers will look for a point important enough to propel them into the rest of the essay. Call that statement at the end of the Introduction a launching point. In the launching point, you whould either make the main point, the central claim that the rest of your text supports, or make a statement that anticipates the central claim. Each of the three grammatical functions of an Introduction contributes to the cognitive framework that readers will use to understand everything that follows.
Readers use characters as the connecting threads out of which they build a coherent story.
They use themes as the connecting threads out of which they build a coherent argument. They use the problem statement to know how what they read relates to their live sand their concerns. And they use the launching point to gain a sense of where your paper will take them. Each one makes it easier for readers to make your essay into the coherent text you hope it will become in their hands. These descriptions are fine for most purposes.