ES|QL is a new piped query language for Elasticsearch. It supports writing composable queries and it features a multi-staged execution. Unlike the other languages supported by Elasticsearch, ES|QL doesn't transpile to Query DSL or use the internal search client: it's based on its own stack. This comes with a sophisticated query analysis and optimisation steps, as well as parallelisation and vectorisation. This talk will give an overview of the execution flow of a query and touch on a few key implementation aspects, following the query from its first syntactic analysis down to Lucene delegation followed by returning the results back to the user, all in a distributed environment.