The Undertaking

S1, E21: Finding it difficult to mend fences with Tommy and Diggle, Oliver instead focuses on crossing another name off the list. While digging through a crooked accountant's laptop, Felicity discovers a transaction that could help Oliver find Walter. To reconfirm the lead, Oliver gambles that Felicity can be counted on in the field for the first time. In a flashback, Malcolm reveals to Robert Queen (guest star JAMEY SHERIDAN) and Frank Chen (guest star CHIN HAN) painful details surrounding his wife's murder, and how that shaped his plans for the Glades. Meanwhile, Tommy stuns Laurel with the truth.