Harvey is taking the gloves-off in Episode 3 of "Suits" Season 4. The episode is titled "Two in the Knees." The preview of the episode indicates that things go from bad to worse, as Harvey and Donna can be seen in the preview video talking about 'they' finding the secret. This secret is likely to be related to Mike's law education fraud.
In the preview clip, Rachel can be seen informing Mike that Harvey is taking his gloves-off. And, Harvey can be seen telling Donna that Mike is on the other side and "I'm not going to warn him." Donna wants Harvey to think something so that Mike's life is not ruined.
Mike almost lost the takeover battle in the previous episode, "Breakfast, Lunch and Dinner." With no other option left, he convinced Walter Gillis to fund the Pension fund with the expansion money and managed to win the first round.
The Episode 3 preview clip suggests that Logan Sanders will not be a happy man because of Harvey's failure to close the takeover deal, as he expected Harvey to take Mike out with one punch. The synopsis of the episode indicates that Logan is set to question Harvey's soft-corner for Mike.
Meanwhile, there will be a misunderstanding between Louis and Malone. In the previous episode, Louis refused to work with Malone because of his shock, dejection and jealousy after Jessica informed him that the SEC man, Malone, he was planning to take down has joined the firm. Donna's intervention helped Louis get back his dignity and the corner office and it looked like he shed his hostility towards Malone. But, it seems it will take a little more time for Louis and Malone to start on a good note. This may perhaps happen when the SEC really comes after the firm.
Donna and Louis bonding was the main highlight of Episode 3. It will be interesting to see what kind of turn Louis and Donna's relationship will take.
Official Synopsis of "Suits" Season 4 Episode 3 "Two in the Knees":
"Logan Sanders, a client of Pearson Specter, looks to Harvey to confirm that his relationship with Mike won't prevent them from winning the takeover battle. Elsewhere, misunderstandings arise between Louis and his new colleague Jeff Malone."