I didn?t want to make the logline too dense, but the reason why he can?t remember one thing, but a lot of other things is his work requires him to erase his memory after every delivery, but his head injury causes the device that erases the memory of his latest job to malfunction, so it wouldn?t target his past, but would affect his current mission – so he wouldn?t remember who hired him, why but he does remember what he has too deliver.