Identify Electrical Issues & Scope of Work

What happens here

The video opens with a demonstration of a circuit breaker immediately tripping. The electrician then explains that a customer called because their circuit breaker keeps tripping. He notes that he has already tried replacing the circuit breaker without success. He walks through the house, showing that various outlets in the kitchen and basement are not working. He uses a Klein Tools RT250 outlet tester to confirm the absence of power at these outlets, indicating a widespread issue on a specific circuit. He states that he can't find any immediate clues as to why the breaker is tripping.

Goal: Diagnose the tripping circuit and understand the full scope of required electrical work.