Dodgy Marie

The idea here is to use Renfield and uncage the Soul to keep Marie flush with resources (and a bit of doom) to keep spells available to use with her ability. She will be equally able to cast attack spells as investigate with a copy of St. Hubert's key, but you'll be focusing on nabbing clues.

Use Marie's high intelligence, St. Hubert's key, and deduction and winging it to nab clues. When you're able to grab the last clue on a location, use Connect the Dots to reap even more. Upgrading to Rites of Seeking allows you to snag multiple clues at once from a location, making it even more likely that you will be able to Connect the Dots.

Use track shoes to keep yourself out of harm's way, wile launching yourself to new locations, and Astral Travel to get into position if there are clues that are desperately needed across the map, or to help resign in situational cases.

You will want to drop Mists for Suggestion (excellent for Marie) and drop Scrying for Feed the Mind (for free card draw, when you have doom) when you are able. Continue to upgrade your rite of seeking and shriveling as well. Eventually, you will likely want to drop the flashlight for a 2nd copy of Rite of Seeking. If you are having difficulties with the encounter sets, you can always drop the delves for Alter Fates.

Steer clear of the the trap of Song of the Dead. Without a reliable way to pull skulls, the damage output is not worth the xp you could be spending elsewhere.

As actual upgrades are scarce in this deck (only seeking and shriveling), you probably want to avoid Arcane Research as well.