Here is a summary of the text: This blog post is part 3 of a series on building a voice-activated movie search app using Amazon Lex, Lambda, and MongoDB Atlas. The author deployed their Lambda function to AWS using the SAM Local tool and tested it in the Amazon Lex console. The Lambda function receives a JSON payload with user-provided parameters and uses an aggregation framework method to query the MongoDB database for movies matching the user's criteria. This approach allows for concise and generic code that can handle multiple cast members, unlike the previous find() method which required manual post-processing logic. The author explains how the aggregation framework pipeline works, including stages such as $match, $sort, $unwind, $group, and $project, to retrieve and process the data in a more efficient and scalable way.