I guess it would be understandable not to show Echoes Act 1 in the OP since it was going to be revealed anyway. David Productions had me worried with their 3-episode rendition of the Nijimura’s Arc but thankfully, we don’t need to waste time with the two weakest “fights” in Part 4. This week, we got Tamami Kobayashi and The Lock and next week we similarly got another one-episode fight with Toshizaku Hazemada.
And wow, looking back, Koichi’s development went through a lot faster than I initially thought. Also, as much as I don’t want to complain about the new visuals, I really hope something happens with Koichi’s fat nose.
Koichi rides his new bike to school and immediately runs over a bag and finds it bloody up and make cat noises. A man sitting on the benches who witnessed this invites Koichi to sit down and chat, and demands him to pay up. The man reveals himself as Kobayashi Tamami, the owner of the cat Koichi just ran over and he demands that Koichi ignore the fact that Tamami had his cat stuffed in a bag out on the street and pay him money. Koichi’s chest begins to feel heavy and Tammai’s stand, The Lock manifests. Tamami is surprised to know that Koichi can see Stands and explains that The Lock will automatically activate on those who feel guilt on a matter associated with Tamami and Koichi’s burden won’t disappear unless he repays him in some way to ease his guilty conscious.
Koichi is asked for some money and he denies having any, and The Lock grows in size, and Tamami notices to realizes that Koichi was lying about money. After snooping around in his wallet, Josuke and Okuyasu show up and threaten Tamami to release The Lock. Okuyasu punches him and Tamami intentionally staggers to the sidewalk curb and smashes his teeth as he falls. Okuyasu begins to feel guilt and he gains The Lock as well. Josuke however finds the dead cat being a complete ruse and all guilt from both Koichi and Okuyasu disappears and Tamami runs off after fooling them with the cut corners of the money he had “returned”.
Koichi returns home to find Tamami massaging his mother’s shoulder and him claiming that his wallet and Koichi’s got swapped. Tamami states that a ridiculous sum of money was inside his wallet and demands it back and “proves” his authenticity by saying what he had on the receipt on his dinner last night. Koichi’s mother begins to doubt her son and the “guilt” of not raising her son right spawns The Lock on her chest. Tamami continues at how he’ll take their house and money and reveals that even Koichi’s sister was made guilty after he feigned burned injuries when she spilled tea on him earlier. Koichi finally loses his patience and manifests his Stand that finally hatches from its egg. Tamami is unable to fight back but Koichi’s Stand is unable to actually hurt him. Tamami fights back but Koichi’s Stand’s powers are revealed to be sound based and Tamami is overtaken by the immense noise from the sounds imprinted on him. Tamami gets to the drawer and takes out a knife and stabs himself lightly but screams loudly enough to have Koichi’s mother enter the room again and Tamami passes the knife to Koichi to frame him. Koichi finds out for another way to use his Stand and implants the word “trust me” onto his mother and she begins to believe in him instead of Tamami’s accusations. Tamami is outed and he takes The Lock off from the Hirose family and begs for forgiveness and the next day, Josuke and Okuyasu find him carrying Koichi’s bag for him.
Lair of the Idle 
The Lock is a perfect Stand to be use by a con artist preying upon those with conscience. Wouldn’t work on without it though, like DIOS. Starting here, we are getting Stands that cannot simply be beaten with overwhelming power. Stand battles are going to become even more battle of wits.
Nothing really new there. Stand fights evolve in more ways than one and Part 4 tends to have a lot more of those battle of wits instead of the more brutal fights shown off in Part 5 and 6.